EP1055897A1 - Heat exchanger with improved fin-positioning - Google Patents

Abstract

The heat exchanger has a series of flat parallel fins (2a, 2b) with holes (21) for tubes and spacers (231, 232) to provide t required interval between adjacent fins. The spacers are in the form of projections made by punching holes through the fins, whi are of a suitable heat conducting material, e.g. aluminium. The fins also have louvred slits (221, 222) for enhanced interaction with the air flow.

Description

The invention relates to a heat exchanger, in particular for motor vehicle. It relates more particularly to a heat exchanger intended to cooperate with an air flow which crosses it, so as to modify the temperature of this flow.

For this purpose, such a heat exchanger comprises a series heat conducting fins, in order to increase its cooperation with the aforementioned air flow. Such fins have a generally planar general shape, and are substantially parallel and spaced apart. Otherwise, they are each provided with openings for the passage of tubes intended to convey a clean fluid to exchange the heat with the air flow.

Generally, the fins are successively stacked the on top of each other. When mounting such a heat exchanger, a sliding of one of the fins relative to the others can happen. The openings of this fin are then, at less partly, obscured by the other fins, which makes the subsequent step of inserting the tubes delicate in the openings.

The present invention improves the situation.

According to a general definition of the invention, each fin has at least one protrusion projecting from a first side, and at least one recess on a second side opposite to the first face, so that the protuberance of a fin is able to cooperate by nesting with the recess a consecutive fin, which allows positioning substantially the fins relative to each other of so that the openings for the passage of the tubes substantially coincide between two consecutive fins.

Advantageously, the fins are made of a material substantially deformable metal and each have at minus a pin forming both the protuberance and the recess cited above.

Preferably, these pins are of substantially shaped conical, with the top of the cone turned towards a fin consecutive.

Typically, these pins have substantially a shape of punctured dome with three sides, each forming a substantially angle less than 90 ° with the aforementioned first side of a fin.

Advantageously, each fin comprises at least two recesses and at least two protuberances suitable for engaging in the recesses of a consecutive fin, in view substantially immobilize the fins, relative to each other to others.

According to another advantageous optional characteristic of the invention, each fin further comprises a plurality spacing stops, intended to rest on one of the first and second faces of a consecutive fin, in view to keep the fins substantially spaced apart by compared to others, and the spacing stops are high substantially less than a height of the protrusions of positioning.

In a preferred embodiment of the heat exchanger heat according to the invention, the aforementioned tubes are substantially in contact with the openings of the fins, in order to mechanically stiffen the assembly formed by the fins and the tubes.

• la figure 1 représente schématiquement un échangeur de chaleur d'un véhicule automobile, muni d'ailettes d'échange thermique ;
• la figure 2 est une vue générale d'une ailette d'un échangeur de chaleur selon l'invention ;
• la figure 3 est une vue de face de l'ailette représentée sur la figure 2 ;
• la figure 4 est une vue selon la coupe IV-IV de la figure 3 ; et
• la figure 5 est une vue du détail V de la figure 2.

Other characteristics and advantages of the invention will appear on examining the detailed description, given below by way of example, and the attached drawings in which:

• Figure 1 schematically shows a heat exchanger of a motor vehicle, provided with heat exchange fins;
• Figure 2 is a general view of a fin of a heat exchanger according to the invention;
• Figure 3 is a front view of the fin shown in Figure 2;
• Figure 4 is a view along section IV-IV of Figure 3; and
• FIG. 5 is a view of detail V of FIG. 2.

The detailed description below and the attached drawings mainly contain elements of character certain. They can therefore not only serve to do better understand the invention, but also contribute to its definition, if applicable.

We first refer to Figure 1 to describe a heat exchanger according to the invention, intended to cool a fluid thanks to an air flow (arrow F) which crosses it. In the example described, this heat exchanger is part the cooling module of a motor vehicle engine, as a cooling radiator.

The exchanger comprises flat tubes 1 arranged in bundles and intended to convey a heat exchange fluid (liquid cooling) of one of the manifolds 4a that includes the heat exchanger, at the other 4b. The extremities tubes are housed, preferably sealed, in openings in the collector plates 3a and 3b, integral with the manifolds 4a and 4b. Tubes 1 which coolant cooperate by exchange thermal with the air flow F, in order to cool said cooling liquid. The heat exchanger has then fins 2, of generally substantially planar shape and substantially parallel to each other. These fins 2 are made of a heat conductive material (comprising aluminum) to increase the surface heat exchange with the air flow F which enters the exchanger, which increases, in general, the cooperation between flow F and the exchanger.

As will be seen below, the conductive fins include spacing means so as to create gaps between the fins, which allows to leave penetrate the air flow F into the exchanger and avoid heat accumulation points. In the example shown in FIG. 1, the fins 2 are substantially perpendicular to the main axes of the tubes 1, and then comprise openings 21 for the passage of the tubes 1.

During the assembly step of such a heat exchanger heat, the fins 2 are stacked on top of each other. Then, the tubes 1, preferably produced in a deformable material, are introduced into the openings 21 stacked fins 2, with a chosen mechanical play. In the manufacturing process of such a heat exchanger, it a stage of expansion of the tubes 1 is then provided, which mechanically stiffens the fins relative to to the tubes, creating in particular a mechanical contact substantially annular between the outer walls of the tubes and the openings 21 of the fins.

It is particularly desired that these fins remain substantially aligned, so that their openings 21 coincide from one fin to the other, which makes it possible to introduce easily the tubes 1 in the openings 21 of the fins consecutive. The openings 21 of these fins must coincide, moreover, with the openings provided in the header plates 3a and 3b.

However, it can happen during the mounting of such exchanger that one of the fins slides out of the stack.

The openings 21 that this fin has are then obscured, at least in part, by the other fins.

According to the invention, the fins of the heat exchanger comprise means for positioning the consecutive fins, so that the fins stacked successively remain substantially aligned with each other, which allows their openings to substantially coincide respective 21.

We now refer to Figure 2 to describe a fin a heat exchanger according to the invention. Fin 2a has openings, substantially in the form of louvers 221 and 222, so as to allow lateral penetration of a part of the air flow F, in order to increase cooperation of the air flow F with the exchanger. Each fin further comprises spacing means 23 with a fin consecutive. These spacing means are formed, in the example described, of stops 23 provided with two walls 231 and 232, forming an angle close to 90 ° with a main surface S of the fin (first side mentioned above). In practice, fins 2 are made of a metallic material deformable, for example aluminum and walls 231 and 232 spacing are obtained by punching on one side of the fins opposite side S (second side mentioned above). The height of walls 231 and 232 defines a general pitch p between consecutive fins (aforementioned interstices).

The openings 21 of the fins are substantially oblong, particularly suitable for tubes 1, flat in the example described. The walls of the openings 21 are intended to be substantially in contact with the tubes.

Referring to Figure 2, the openings 21 of a fin 2b substantially coincide with the openings 21 of a consecutive wing 2a. This coincidence of openings is ensured by means of positioning which comprise the fins of the heat exchanger according to the invention. These positioning means are produced in the form of a substantially conical pin, in particular frustoconical, performed, for example, by punching a bottom face fin 2a.

Referring to the detail figure 5, the protuberance formed by punching has a general shape of a punctured dome three sides 241, 242 and 243, these sides forming an angle less than 90 ° with the main surface S of the fin.

Referring to Figure 4, showing a sectional view transverse of two consecutive fins 2a and 2b, the spacing walls 231 and 232 are substantially curved laterally at their ends and thus have a shape general of collar. Furthermore, the height h of the spike positioning 24 is greater than the height p of the stop of spacing 23. Thus, the sides 241, 242 and 243 of a fin 2b fit into the recess that forms the punching of positioning of a consecutive fin 2a, while the spacing walls 231 and 232 come into contact with the main surface of the consecutive fin 2a.

Advantageously, each fin has two pins positioning 24a and 24b (Figure 3), which allows substantially immobilize the fins, relative to each other to others.

Thus, according to one of the major advantages which the present invention, the fins can be substantially immobilized in relation to each other in progress stacking, which facilitates the introduction of the tubes into the openings 21.

According to another advantage which the invention provides, the two positioning pins 24a and 24b also allow to index the fins, in relation to each other, in the case (not shown) where these do not present any double axial symmetry.

Of course, the present invention is not limited to the embodiment described above by way of example. She extends to other variants.

It will thus be understood that the positioning means 24 described above can form both means of positioning and spacing means between the fins.

These positioning means are produced by punching the fins. As a variant, these may include a protuberance formed on one side, as well as a recess formed on the other side. If it is particularly desired to train a heat exchanger with tubes inclined at an angle different from 90 ° to the fins, it can be envisaged to shift, in the plane of a fin, the recess of the protuberance it entails.

The shape of the positioning protrusions produced by punching and having three sides (or lips) 241, 242 and 243 is described above by way of example. So general, positioning punches may be provided substantially frustoconical, or even conical, with the top of the cone turned towards a consecutive fin.

The invention advantageously applies to an exchanger heat produced by mechanical assembly of flat tubes and substantially planar shaped fins, substantially perpendicular to the tubes.

Claims (8)

Heat exchanger, in particular for a motor vehicle, of the type comprising a series of fins (2a, 2b) substantially planar, substantially parallel and spaced apart, each provided with openings (21) for the passage of tubes (1) of heat exchange,
characterized in that each fin (2a) has at least one protuberance projecting from a first face (S), and at least one recess on a second face opposite to said first face, while the protuberance (24) of a fin (2b) is adapted to cooperate by fitting with the recess of a consecutive fin (2a), which allows the fins to be positioned substantially in relation to each other, so that the openings (21) for the passage of the tubes substantially coincide between two consecutive fins (2a, 2b). Heat exchanger according to claim 1, characterized in that the fins (2) are made of a material substantially deformable metal, and in that the fins each have a pin (24) to form both a protuberance on the first face (S) and a recess in the second opposite side. Heat exchanger according to claim 2, characterized in that said pins (24) are substantially shaped conical. Heat exchanger according to claim 3, characterized in that the pins (24) have substantially a shape three-sided punctured dome (241,242,243). Heat exchanger according to claim 4, characterized in that each panel (241,242,243) forms an angle substantially less than 90 ° with the first side (S) of the fin. Heat exchanger according to one of claims previous, characterized in that each fin has at at least two recesses and at least two protrusions (24a, 24b) suitable for engaging in the recesses of a fin consecutive, in order to immobilize the fins appreciably, relative to each other. Heat exchanger according to one of claims previous, characterized in that each fin (2) has furthermore a plurality of spacing stops (23), intended to lean on one of the first and second faces (S) of a consecutive fin, in order to maintain the fins substantially spaced from each other, and in that the spacers (23) are of height (p) substantially less than a height (h) of the protrusions positioning (24). Heat exchanger according to one of claims previous, characterized in that the tubes (1) are substantially in mechanical contact with said openings (21) fins.

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