FR3081199A1 - SEAL FOR MOTOR VEHICLE HEAT EXCHANGER AND HEAT EXCHANGER COMPRISING THIS SEAL - Google Patents

Abstract

Seal (1) for heat exchanger (2) in which said seal (1) comprises a plurality of peripheral tabs (10), each of said tabs being intended to come into contact with a part of the exchanger (2) heat, and wherein said seal (1) comprises (only) two compression pins (11) passing through said peripheral tabs (10).

Description

The invention relates to the field of heat exchangers for a motor vehicle and more particularly to the seals of these heat exchangers.

The vehicles are largely equipped with heat exchangers. As a non-exhaustive example, these heat exchangers are used in the air cooling systems of an engine's charge air.

The heat exchanger is generally in the form of a bundle of horizontal tubes superimposed on each other and in which the heat transfer fluid circulates. The tubes open out at their longitudinal ends through a collecting plate.

In order to uniformly distribute the fluid in the tubes of the heat exchanger, it comprises one or more manifold (s) in relation to the tubes.

The manifold is attached and tightly fixed to the manifold plate. Sealing is achieved using one or more seals. The latter are generally arranged in a peripheral groove along the edges of the collector plate.

The tightness between the manifold and the manifold plate is of major importance for the proper functioning of the heat exchanger. A leak is affecting the performance of the heat exchanger and may constitute a fault that the vehicle owner must repair by replacing the defective heat exchanger. In fact, the manifolds are generally mounted on the manifold plates permanently.

Heat exchangers are elements designed to operate throughout the life of the vehicle, or at least for a large part of it.

The seal is subject to extreme temperature conditions and variations. It wears out over time and may no longer provide a seal between the manifold and the manifold.

Injunction seals between a manifold and a manifold have been known for a long time. They are arranged so that they have a large contact surface between their external walls and the parts of the heat exchanger, namely the manifold plate and the manifold. The pressure on the seal is then uniformly distributed over the entire contact surface which corresponds to all or most of the dimensions of the seal. The seal is compressed in its entirety and comprises only one compression axis.

These seals have the major drawback of a leak when they are subjected to salt spray tests.

It has in particular been established by the depositor that at a given compression rate, these seals have a containment rate so high that the deformation thereof makes it difficult to assemble and crimp the manifold on the manifold plate and generates significant mechanical stresses harmful to the seal. This reduces its effectiveness and / or can cause leaks.

An objective of the invention is to remedy at least one of the aforementioned drawbacks.

Another objective of the invention is to provide a reliable seal, even under the conditions of salt spray tests.

Another objective of the invention is to reduce the rate of containment of seals.

Another object of the invention is to facilitate the mounting of the manifold on the manifold of the heat exchanger.

The invention relates to a seal for a heat exchanger in which said seal comprises a plurality of peripheral tabs, each of said tabs being intended to come into contact with a part of the heat exchanger, and in which said seal comprises two compression axes passing through said peripheral lugs.

This seal advantageously makes it possible to ensure a lasting and excellent quality seal. Indeed its containment rate is reduced compared to known seals. In addition, the mounting of the manifold on the manifold is facilitated.

Several additional features of the invention can be taken alone or in combination:

each peripheral leg is separated from one another by a cavity;

said peripheral legs are four in number;

two of said peripheral legs form a first pair, called first side pair, the other two of said peripheral legs form a second pair, said second side pair, each of the compression axes passing through one of said side pairs;

each peripheral leg of the first lateral pair is opposite to a peripheral leg of the second lateral pair, these peripheral legs opposite one another are asymmetrical, so that by extending the lateral walls of a peripheral leg, these side walls do not coincide with the side walls of the opposite peripheral leg;

this includes a central portion from which project, the peripheral legs;

the latter has in cross section a first axis of symmetry;

the latter has in cross section a second axis of symmetry perpendicular to the first axis of symmetry;

it has a central symmetry in cross section;

each peripheral tab has a rounded end;

this comprises one or more first portions having in cross section a first predetermined shape and one or more second portions having in cross section a second predetermined shape different from the first shape;

the latter has a closed contour comprising a plurality of straight portions forming said first portions and a plurality of bent portions forming said second portions, each bent portion defining a junction between two successive straight portions;

said first and second lateral pairs are more spaced from one another in the at least one bent portion than in said one or said straight portions;

the rectilinear portions have in section upper legs and lower legs defining lateral cavities of which a concavity is turned towards the outside, said lateral cavity defining an angle measured between two faces immediately adjacent to an upper leg and a lower leg , said angle being between 95 and 115 degrees, preferably 100 degrees;

the upper legs define between them an upper cavity and the lower legs define between them a lower cavity, said upper and lower cavities having an angle measured respectively between the upper legs and lower legs, said angle being less than the angle of the lateral cavities ;

the angle between the upper legs and the angle between the lower legs is between 95 and 115 degrees, preferably 100 degrees;

the bent portions have, in section, upper legs and lower legs defining lateral cavities of which a concavity is turned towards the outside, said lateral cavity defining an angle measured between two faces immediately adjacent to an upper leg and a lower leg , said angle being between 95 and 115 degrees, preferably 100 degrees;

the upper legs define between them an upper cavity and the lower legs define between them a lower cavity 22, said upper and lower cavities having an angle measured respectively between the upper legs and lower legs, said angle being greater than the angle of the cavities lateral;

the angle between the upper legs and the angle between the lower legs is between 70 and 90 degrees, preferably 80 degrees.

The invention secondly relates to a heat exchanger, in particular for a motor vehicle, comprising a seal as previously described.

Other features and advantages of the invention will become apparent in the description below in relation to the appended drawings, given by way of non-limiting examples:

Figure 1 is a top view of a seal according to the invention;

Figure 2 is a sectional view along the cutting axis A-A of Figure 1;

Figure 3 is a sectional view along the cutting axis B-B of Figure 1;

Figures 4 and 5 are views similar to Figure 2, and show alternative embodiments;

Figure 6 is a schematic perspective view of a heat exchanger;

Figure 7 is a schematic view partially illustrating in cross section, a manifold a seal and a manifold of an exchanger according to the invention.

In Figure 1 is shown a seal 1 for heat exchanger.

As previously mentioned, heat exchangers 2 comprise a bundle 3 of tubes, the latter are not illustrated, and a manifold box 4. The heat exchanger 2 further comprises a collecting plate 30 through which the tubes open into the collecting box 4. The collecting box 4 is attached and fixed in a sealed manner to the collecting plate 30. The seal is obtained using the seal. The latter is arranged in a peripheral groove 5 along the edges of the collecting plate 30 as illustrated in FIGS. 6 and 7. The peripheral groove 5 comprises rectilinear zones 6 and angled zones 7.

The seal 1 has a generally substantially rectangular outline. Thus, the seal 1 has a closed contour. It comprises a plurality of substantially rectilinear portions and a plurality of bent portions. The bent portions define a junction between two successive straight portions. The rectilinear portions and the bent portions respectively accommodate in the rectilinear zones 6 and the bent zones 7 of the peripheral groove 5 of the collecting plate 30.

The rectilinear portions have in section a first predetermined shape shown in FIG. 2. The bent portions have in section a second predetermined shape different from the first shape and illustrated in FIG. 3. Sections of different shapes advantageously allow the joint to adapt to the specificities of the peripheral groove 5 while using only one joint.

The seal 1, both in its rectilinear and bent portions, comprises several peripheral tabs 10. The peripheral tabs 10 are suitable and intended to come into contact with the collector plate 30 and / or the collector box 4, at the level of the groove 5. The joint has in section a shape reminiscent of that of the letter X.

In the embodiments shown in the figures, the straight and bent portions have four peripheral tabs 10. Thus the seal 1 has two compression axes IL

Two compression axes 11 advantageously make it possible to improve the seal compared to traditional seals which include only one. The seal 1 according to the invention provides two levels of sealing, namely a first level of sealing materialized by a first axis 11 of compression and located on the outside of the peripheral groove 5 and a second level of sealing materialized by a second compression axis 11 and located on the inside of the peripheral groove 5. The first level of sealing aims to prevent the entry of external fluids into the heat exchanger 2 and the second level of sealing aims to seal against the internal pressure of the heat transfer fluid.

In addition, the seal is improved due to the greater rigidity of the rubber. This greater rigidity compared to conventional seals is obtained thanks to the specific shape of the seal 1 making it possible to obtain the two compression axes 11 instead of just one.

The upper legs 13 and the lower legs 14 converge and are connected to the center of the joint by a central portion 15. The central portion 15 is common to all the peripheral legs 10. In other words, the peripheral tabs 10 project from the central portion 15.

The seal 1 has in cross section a first axis 17 of vertical symmetry. The seal 1 still has, in cross section, a second axis 18 of horizontal symmetry, perpendicular to the axis of vertical symmetry. Finally, the seal 1 has a central symmetry in cross section, that is to say a symmetry with respect to a point located in the center. These symmetries make it easier to position the seal 1.

In the seal 1 seal, each peripheral tab 10 faces another opposite peripheral tab 10. An opposite peripheral tab 10 is a peripheral tab 10 which is not immediately adjacent. Two opposite peripheral legs 10 are advantageously offset from one another. Thus by extending the side walls of a peripheral tab 10, these do not coincide with the side walls of the opposite peripheral tab 10.

This asymmetry with respect to a diagonal axis 19 advantageously makes it possible to improve the gain in volume of the joint when the latter is compressed.

In what follows, the peripheral tabs 10 will be grouped in pairs according to a grouping different from that mentioned above:

a pair of upper legs 13 collaborating with the collecting box 4, and a pair of lower legs 14 collaborating with the collecting plate 30.

The seal 1 defines between the upper legs 13 and the lower legs 14, on either side, a lateral cavity 16. The lateral cavity 16 defines a concavity facing outwards from the seal 1. The lateral cavity 16 defines an angle measured between two faces immediately adjacent to an upper tab 13 and a lower tab 14. The angle is between 95 and 115 degrees, preferably 100 degrees.

The upper legs 13 are separated from each other by an upper cavity 21. The lower legs 14 are separated from each other by a lower cavity 22.

The upper and lower cavities 21, 22 define an angle between 95 and 115 degrees, preferably 100 degrees. The angle is measured between the neighboring faces of the upper legs 13 for the upper cavity 21 and between the faces of the lower legs 14 for the lower cavity 22.

This contributes to obtaining a volume gain of between 10 and 20% compared to traditional joints.

Advantageously, the lateral cavities define an opening angle greater than that of the upper and lower cavities 21, 22.

This advantageously makes it possible to reduce the spreading of the seal when it is compressed.

Each peripheral tab 10 comprises two lateral edges connected to each other by the peripheral ends 12. The side edges are parallel to each other so that the thickness of the peripheral tabs 10 is substantially constant.

The peripheral 12 ends of the peripheral 10 legs are rounded. They connect the lateral edges of each peripheral tab 10, for example, in a semicircle. This geometry allows the peripheral legs 10 to best adapt to the collecting plate 30 and to the collecting box.

Figures 2, 4 and 5 show in section several alternative embodiments of the seal 1 in its rectilinear portions.

As previously mentioned, the bent portions have a section of shape different from that of the rectilinear portions as can be seen in FIG. 3.

This advantageously allows the bent portions to adapt to the bent areas in a heat exchanger 2.

The peripheral tabs 10 form a first pair, called the first lateral pair. The other two peripheral lugs 10 forming a second pair, called the secondary side pair. Each of the compression axes passes through one of the lateral pairs.

Furthermore, said first and second lateral pairs are more spaced apart from one another in said bent portion (s) than in said straight portion (s).

Like the straight portions, the seal 1 in the bent portions has generally the same characteristics. However, its shape differs in that it has an elongated central portion 20 so that the upper legs 13 are more apart from each other. It is the same for the lower legs 14.

Another difference with the rectilinear portions is that the angle formed by the upper cavity 21 (identical to that of the lower cavity 22) is between 70 and 90 degrees; preferably 80 degrees. The angle formed by the upper cavity 21 is greater than the angle formed by the lateral cavity 16, which is between 95 and 115 degrees, preferably 100 degrees.

As with the rectilinear portions, this advantageously makes it possible to contribute to obtaining a gain in volume of between 10 and 20% compared to traditional joints.

In the bent portions, the joint may have a different orientation from that which it adopts in the rectilinear portion.

The peripheral tabs 10 of the straight and bent portions have a thickness of between 0.8 and 1 millimeter.

Comparative tests carried out by the applicant between the embodiments of the invention and a standard seal gave the results below.

Standard seal Figure 2 + figure 3 Figure 4 + figure 3 Figure 5 + figure 3 Compression ratio 35% 35% 35% 35% Rate containment 104% 84% 87% 95%

As illustrated in the table above, for a compression rate of 35% the confinement rate of a standard joint is greater than 100%. The seal then tends to go up, making it difficult to crimp the collecting box 4 onto the collecting plate 30. This also implies significant constraints on the seal 1 at the expense of the quality of the seal and its longevity.

In parallel, a gasket 1 having in its rectilinear portions one of the shapes illustrated in FIGS. 2, 4 and 5 and in its bent portions the shape illustrated in FIG. 3, has a compression ratio of 35%, a containment rate of less than 100%, thus guaranteeing a good seal and a long service life.

In Figure 6, there is illustrated a heat exchanger 2, in particular for a motor vehicle.

Referring to FIG. 7, it can be seen that the manifold box 4 comprises a part 40 used to compress the seal, called the foot of the box, having a bearing face 42 which is advantageously flat.

The collecting box 4 is, for example, crimped on the collecting plate 30.

Claims (14)

1. Gasket (1) for a heat exchanger (2) characterized in that said gasket (1) comprises a plurality of peripheral tabs (10), each of said tabs being intended to come into contact with a part of the heat exchanger (2), and in that said seal (1) comprises two axes (11) of compression passing through said peripheral tabs (10). 2. A seal (1) for sealing according to claim 1 in which each peripheral tab (10) is separated from one another by a cavity. 3. Seal (1) sealing according to one of claims 1 or 2, wherein said tabs (10) are four in number. 4. Seal (1) seal according to claim 3, wherein two of said peripheral tabs (10) form a first pair, called first side pair, the other two of said peripheral tabs (10) forming a second side pair, called secondary lateral pair, each of the compression axes passing through one of said lateral pairs. 5. Seal (1) seal according to claim 4, wherein each tab (10) peripheral of the first side pair is opposite a tab (10) peripheral of the second side pair, these tabs (10) opposite l 'to each other are asymmetrical, so that by extending the side walls of a peripheral tab (10), these side walls do not coincide with the side walls of the opposite peripheral tab (10). 6. Seal (1) for sealing according to one of the preceding claims comprising a central portion (15) from which project, the peripheral tabs (10). 7. Seal (1) for sealing according to one of the preceding claims having in cross section a first axis (17) of symmetry. 8. Seal (1) for sealing according to claim 7 having in cross section a second axis (18) of symmetry perpendicular to the first axis (17) of symmetry. 9. Seal (1) for sealing according to one of claims 7 or 8 having in cross section, a central symmetry. 10. Seal (1) for sealing according to one of the preceding claims, in which each peripheral tab (10) has a rounded end. 11. A seal (1) according to one of the preceding claims comprising one or more first portions having in cross section a first predetermined shape and one or more second portions having in cross section a second predetermined shape different from the first shape. 12. Seal (1) seal according to claim 11 wherein it has a closed contour comprising a plurality of straight portions (8) forming said first portions and a plurality of angled portions (9) forming said second portions, each bent portion defining a junction between two successive straight portions (8). 13. A seal (1) for sealing according to claim 5, in which said first and second lateral pairs are more spaced from one another in said bent portion (s) than in said straight portion (s). 14. Heat exchanger, in particular for a motor vehicle, comprising a seal according to any one of the preceding claims.