EP3198209B1 - Heat exchanger, especially for motor vehicle, and method for producing such a heat exchanger - Google Patents

Description

The present invention relates to a heat exchanger and a method of manufacturing such an exchanger. It is particularly aimed at applications in the field of motor vehicles, in particular as a radiator for cooling the coolant used for cooling the engine of the vehicles.

In automotive applications, two main types of heat exchangers are known, a first type, referred to as mechanical, corresponding to exchangers obtained by assembling their components by deformation of material, and so-called brazed exchangers, corresponding to exchangers obtained. by assembling their components by soldering.

The mechanical exchangers consist mainly of a bundle of tubes in which circulates a coolant and a plurality of fins disposed perpendicularly to the tubes and provided with orifices through which said tubes. The fins have the function of increasing the exchange surface with the air passing through the exchanger. This gives a heat exchange between the fluid flowing in the tubes and the air passing between the fins.

The fins are held on the tubes and the tubes are held on the collector plates by means of an expansion of the tubes. More specifically, an expansion olive is passed along the tubes, inside of them. It has the effect of deforming the material of the tubes by increasing their section and thus allows them to be applied against the fins.

An interest of mechanical exchangers compared to brazed exchangers is their great ease of assembly. Indeed, brazed exchangers require brazing furnaces forcing heavy investments while mechanical exchangers can be produced with much less heavy investment facilities.

However, in the mechanical exchangers, the collector plate and the tubes are made of metal and are subject to corrosion. Such a phenomenon is further amplified by a stack effect between the collector plate and the tubes. Corrosion weakens the tubes and / or the header plate and poses a risk to the tightness of the exchanger.

To overcome this drawback, it has already been proposed collector boxes of plastic. These are tubular in shape and provided with a passage hole for the tubes. With such a solution, however, it is difficult to expand the tubes given the space available inside the box. The immobilization of the tubes relative to the boxes poses the problem.

The document US 2011/120671 describes in particular a heat exchanger according to the preamble of claim 1.

The present invention aims to remedy these drawbacks and firstly relates to a heat exchanger, according to the title of the independent claim 1.

The collector plate being made of plastic material, it avoids the corrosion phenomena encountered with the metal collector plates of the state of the art. In addition, by connecting the tubes to the box through the holding plate, the problem of immobilization of the tubes with respect to the boxes is solved.

• ladite plaque de maintien est rapportée extérieurement sur ladite boîte,
• ladite plaque de maintien est rapportée sur ladite plaque collectrice,
• ladite boîte comprend un couvercle, rapporté sur ladite plaque collectrice,
• ledit couvercle est en matériau plastique,
• ledit couvercle et ladite plaque collectrice sont fixés par soudage,
• lesdits tubes sont métalliques,
• lesdits tubes sont en alliage d'aluminium,
• ledit échangeur comprend, selon l'invention, en outre un joint traversé par lesdits tubes,
• ledit joint est, selon l'invention, situé à l'extérieur de ladite boîte collectrice,
• ledit joint est comprimé entre lesdits tubes et ladite plaque collectrice au niveau d'un contour desdits orifices prévus dans ladite plaque collectrice pour le passage desdits tubes,
• lesdits tubes présentent un évasement au niveau de leurs extrémités,
• ledit évasement s'étend au moins en regard de ladite plaque de maintien et/ou de ladite plaque collectrice, voire en regard dudit joint,
• ladite plaque de maintien est amovible par rapport à ladite boîte collectrice.

According to different embodiments that can be taken together or separately:

• said holding plate is externally attached to said box,
• said holding plate is attached to said header plate,
• said box comprises a lid, attached to said collector plate,
• said lid is made of plastic material,
• said cover and said collector plate are fixed by welding,
• said tubes are metallic,
• said tubes are made of aluminum alloy,
• said exchanger comprises, according to the invention, in addition a seal traversed by said tubes,
• said seal is, according to the invention, located outside said collecting box,
• said seal is compressed between said tubes and said header plate at a contour of said holes provided in said header plate for passage of said tubes,
• said tubes have a flare at their ends,
• said flaring extends at least opposite said holding plate and / or said collector plate, or even facing said seal,
• said holding plate is removable relative to said manifold.

• une étape de fixation desdits tubes sur ladite plaque de maintien,
• une étape d'accrochage de ladite plaque de maintien sur ladite boîte collectrice.

The invention also relates to a method of manufacturing such an exchanger, said method comprising:

• a step of fixing said tubes on said holding plate,
• a step of hooking said holding plate on said manifold.

• ladite étape de fixation des tubes dans la plaque de maintien comprend une étape d'évasement desdits tubes dans ladite plaque de maintien,
• ledit procédé comprend une étape d'introduction desdits tubes dans ladite plaque collectrice,
• ladite étape d'introduction des tubes dans ladite plaque collectrice est postérieure à l'étape de fixation desdits tubes sur ladite plaque de maintien et/ou antérieure à l'étape d'accrochage de ladite plaque de maintien sur ladite boîte collectrice,
• ladite étape d'introduction desdits tubes dans ladite plaque collectrice comprend une étape d'emmanchage à force desdits tubes dans ladite plaque collectrice et/ou ledit joint.

According to various embodiments of the invention that can be taken together or separately:

• said step of fixing the tubes in the holding plate comprises a step of flaring said tubes in said holding plate,
• said method comprises a step of introducing said tubes into said collecting plate,
• said step of introducing the tubes into said collector plate is subsequent to the step of fixing said tubes on said holding plate and / or prior to the step of hooking said holding plate onto said collecting box,
• said step of introducing said tubes into said header plate comprises a step of forcing said tubes into said header plate and / or said seal.

• La figure 1 est une vue en élévation illustrant de façon schématique un échangeur conforme à l'invention.
• La figure 2 est une vue éclatée en perspective d'une boîte collectrice d'un échangeur de chaleur conforme à l'invention.
• La figure 3 est une vue partielle en perspective d'un faisceau d'un échangeur de chaleur conforme à l'invention.
• La figure 4 est une vue en perspective montrant le montage du faisceau de la figure 3 sur la boîte collectrice de la figure 2.
• La figure 5 est une vue en perspective montrant un exemple d'échangeur de chaleur conforme à l'invention, après montage.
• La figure 6 est une vue en perspective montrant une variante de réalisation, conforme à l'invention, de l'échangeur de la figure 5.

The appended figures will make it clear how the invention can be realized. In these figures, identical references designate similar elements.

• The figure 1 is an elevational view schematically illustrating an exchanger according to the invention.
• The figure 2 is an exploded perspective view of a header of a heat exchanger according to the invention.
• The figure 3 is a partial perspective view of a beam of a heat exchanger according to the invention.
• The figure 4 is a perspective view showing the beam assembly of the figure 3 on the collector box of the figure 2 .
• The figure 5 is a perspective view showing an example of heat exchanger according to the invention, after assembly.
• The figure 6 is a perspective view showing an alternative embodiment, according to the invention, of the exchanger of the figure 5 .

As illustrated in figure 1 the invention relates to a heat exchanger 1 between a first and a second fluid. This is a mechanical type exchanger. It comprises a bundle of tubes 3, in which the first fluid circulates, namely here a heat transfer fluid. Said coolant is, for example, brine, especially when the heat exchanger 1 serves as a cooling radiator of a heat engine.

Said tubes 3 are, for example, of circular, oval or oblong cross section. In the latter case, their cross section may have concave zones giving the tubes a reduced passage section in their central zone. Said tubes 3 are, for example, a metal alloy such as an aluminum alloy. They are obtained, in particular, by electro-welding.

Said beam may further comprise fins cooling or heat dissipation 4, through which the tubes 3. The latter are, for example, aligned in parallel, in one or more rows and the fins 4, provided parallel to each other, are arranged transversely , in particular perpendicular to said tubes 3. To simplify the drawing, only a limited number of fins of the beam has been shown.

The fins 4 are provided with passage orifices of tubes of shape corresponding to the cross section of said tubes. They may also have louvers for disrupting the flow of the second fluid, namely here a flow of incident air. In this way, the heat exchange between said air flow, circulating between the fins 4, and the heat transfer fluid circulating in the tubes 3 is favored. Said fins 4 are separated from each other by a step that is advantageously constant. .

Said exchanger further comprises two end manifold boxes 2 spaced parallel to each other and connected by the tubes 3. Said tubes 3 and said boxes 2 allow the circulation of said first fluid between them. Preferably, the dimensions of the fins 4, in plan, correspond substantially to those of the manifolds 2 for the purpose of compactness of the heat exchanger 1.

In the case of an application as a cooling radiator of a motor vehicle engine, the heat transfer fluid from the tubes and passing through one of the manifolds, is fed, via a supply line, to the various organs hot engine (engine block, cylinder head, ...) to cool to be returned, while being heated, by a return pipe to the other manifold of the radiator to circulate again in the tubes. The heat exchange between the hot coolant circulating in the heat exchanger tubes and the air flow passing between said tubes for lowering the temperature of the coolant is favored by the presence of the fins whose shape, number and the material are chosen to optimize the evacuation of a large amount of heat in order to gradually bring the heat transfer fluid through the exchanger to an acceptable and effective temperature range for cooling the engine. The fluid supply and return connections provided in the respective boxes leading to and from the engine have not been shown.

Said boxes 2 comprise a manifold plate 6 provided with passage orifices of said tubes 3. Said boxes 2 further comprise here a cover 8, attached to said manifold plate 6. Said cover 8 is, for example, of plastic material. This is, in particular, polyamide, in particular PA 6.6.

As is best seen in the figure 2 , said cover 8 may have reinforcing ribs 10. It may also incorporate one or more flanges 12 for fixing the exchanger, here located at its longitudinal ends, and / or one or more inlet pipes 14 and / or outlet of the first fluid, here located between its longitudinal ends.

According to the invention, said collecting plate is made of plastic material, in particular polyamide, in particular PA 6.6. Such a choice of material makes it possible to limit the effects of corrosion.

To the figure 2 the cover 8 and the collector plate 6 are shown separately. Said cover 8 and said collector plate 6 may advantageously be fixed to one another by welding, especially by vibration, ultrasound, infrared, laser, heating or other.

As illustrated in figure 3 said heat exchanger further comprises a plate 16 for holding said tubes 3. It is here provided such a plate of maintaining 16 near each longitudinal end of said tubes 3. Said plate 16 is, for example, pierced with orifices 18 through which the tubes 3 are maintained. In other words, said tubes 3 and said holding plate 16 are integral with each other, preferably in a non-removable manner. Said plate 16 is, for example, metallic. It is here of substantially rectangular shape.

It should be noted in particular that said holding plate 16 is different from the fins 4. In particular, it is more resistant than these, in particular by the choice of a material and / or a thickness of different material.

To the figure 4 , the assembly of the heat exchanger bundle is shown on the box 2, according to the arrow marked 20.

As illustrated in the following figures, at the end of this assembly, each holding plate 16 is fixed on one of the boxes 2. This ensures the immobilization of the tubes 3 relative to the boxes 2. Here, said plates 16 are externally reported on said boxes 2 and more particularly on said collector plates 6.

To ensure a good seal between the boxes 2 and the tubes 3, the latter are advantageously force-fitted into said collector plate 6. To further improve this result and how it is more visible in the figure 4 said exchanger may comprise a seal 22, in particular elastomer, traversed by said tubes 3.

Said seal 22 advantageously has for this purpose orifices 24 passages of the tubes. Said seal 22 here has a flat portion connecting annular parts, substantially projecting, forming sleeves or teats 26 at which said orifices 24 for passage of the tubes through the seal 22 are defined. In other words, each of said tubes 3 passes through one of said sleeves 26. Said seal 22 here is located outside said manifold 2.

Said seal 22 is compressed between said tubes 3 and said header plate 6, at a contour of said orifices 24 provided in said manifold plate 6 for the passage of said tubes 3. In other words, here, the sleeves 26 are compressed, in line with said manifold plate 6, between the tubes 3 and a contour of the passage orifices of said tubes 3 formed in said header plate 6. In other words, a portion of the sleeves 26 is inserted into said passage orifices of the tubes 3 formed in the collector plate 6, or even extends axially to the inside of the manifold 2.

Said tubes 3 advantageously have a flare 28 at their longitudinal ends. Said flaring 28 extends at least opposite said holding plate 16, said seal 22 and said collecting plate 6. Such a flare 28 promotes the holding of the tubes 3 in said holding plate 16, forcing them into the collector plate 6 and compression of the seal 22 between said tubes 3 and the collector plate 6.

As illustrated in Figures 5 and 6 said holding plate 16 is removable relative to said manifold 2.

To the figure 5 said holding plate 16 is secured to the header plate 6 by lugs 30 provided on said header plate 6 and slots 32 provided on said holding plate 16, said lugs 30 snapping into said slots 32.

To the figure 6 said holding plate 16 is secured to the collector plate 6 by crimping. For this, said manifold plate 6 is provided with housings 34, here regularly distributed along its periphery, at which crimping teeth 36 of the holding plate 16 are located.

A method of manufacturing an exchanger as described above is described below.

According to the invention, said tubes 3 are fixed on said holding plate 16, for example by flaring of the end of said tubes.

A prior step of fixing the fins 4 may take place, also by flaring. For this, we can circulate an expansion olive deforming the tubes to a diameter slightly greater than that of the orifices provided in the fins 4 for the passages of said tubes. The flaring of the end of the tubes then takes place in a second time, to a still greater diameter.

Moreover, said manifold 2 is assembled, in particular by welding of the collecting plate 6 and the cover 8.

In a subsequent step, said holding plate 16, and therefore the heat exchange bundle, is hooked onto said manifold 2, in particular by means of said lugs 30 and / or by crimping.

In advance, these tubes 3 have advantageously been introduced into said collecting plate 6, in particular by forcing said tubes 3 into said collecting plate 6, thereby compressing the seal 22.

Claims (13)

1. Heat exchanger, notably for a motor vehicle, said exchanger comprising a core bundle for the exchange of heat between a first and a second fluid, said core bundle comprising a plurality of tubes (3) and a header tank (2), said tubes (3) and said tank (2) allowing said first fluid to circulate between them, said exchanger further comprising a retaining plate (16) for holding said tubes (3), said plate (16) being fixed to said tank (2), said tank (2) comprising a collector plate (6) provided with orifices through which said tubes (3) pass, said collector plate (6) being made of plastic, characterized in that said exchanger further comprises a gasket (22) through which said tubes (3) pass, said gasket (22) being situated outside said header tank (2).
2. Exchanger according to the preceding claim, in which said retaining plate (16) is attached externally to said tank (2).
3. Exchanger according to either one of the preceding claims, in which said retaining plate (16) is attached to said collector plate (6).
4. Exchanger according to any one of the preceding claims, in which said tank (2) comprises a cover (8), attached to said collector plate (6).
5. Exchanger according to the preceding claim, in which said cover (8) is made of plastic.
6. Exchanger according to either one of Claims 4 and 5, in which said cover (8) and said collector plate (6) are fixed by welding.
7. Exchanger according to Claim 1, in which said gasket (22) is compressed between said tubes (3) and said collector plate (6) at an outline of said orifices provided in said collector plate (6) for the passage of said tubes (3).
8. Exchanger according to any one of the preceding claims, in which said tubes (3) are flared (28) at their ends, said flare (28) extending at least facing said retaining plate (16) and/or said collector plate (6).
9. Exchanger according to any one of the preceding claims, in which said retaining plate (16) is removable with respect to said header tank (6).
10. Method of manufacturing an exchanger according to any one of the preceding claims, said method comprising:

    - a step of fixing said tubes (3) to said retaining plate (16),

    - a step of attaching said retaining plate (16) to said header tank (2).
11. Method according to the preceding claim, in which said step of fixing the tubes (3) in the retaining plate (16) involves a step of flaring said tubes (3) in said retaining plate (16).
12. Method according to either one of Claims 10 and 11, in which said method comprises a step of introducing said tubes (3) into said collector plate (6), after the step of fixing said tubes (3) to said retaining plate (16) and/or before the step of attaching said retaining plate (16) to said header tank (2).
13. Method according to Claim 12, in which said step of introducing said tubes (3) into said collector plate (6) comprises a step of force-fitting said tubes (3) into said collector plate (6).

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