WO2000033009A1 - Method for assembling a heat exchanger - Google Patents

Abstract

The invention concerns a method for assembling a collector plate (18) and a collector box (38) of a heat exchanger, in particular for a motor vehicle, which consists in: pressing on the collector box (38) to compress at least partly a sealing joint (28); crimping the crimping means (26) to mutually assemble the collector plate (18) and the collector box (38), and maintaining the opposite sides (50) of the collector box (38) to maintain a substantially constant spacing between said sides (50) and preventing them from coming closer to each other, in particular during the crimping process. The invention is useful for producing heat exchangers with reduced space requirement.

Description

Method of assembling a heat exchanger

The invention relates to heat exchangers, in particular for motor vehicles.

It relates more particularly to a method of assembling a collector plate and a collector box of a heat exchanger, in which the collector plate is provided with crimping means capable of coming to bear against a peripheral rim, also called "heel", of the manifold by compressing a seal.

A heat exchanger of this type further comprises a bundle of tubes and fins, in which the ends of the tubes are introduced into holes in the header plate. Thus, when the manifold plate and the manifold are tightly assembled, they jointly define a volume or compartment which communicates with the tubes of the bundle.

The method, object of the invention, is of the type comprising a pressing operation exerted on the manifold to compress at least partially the seal, and a crimping operation exerted on the crimping means to carry out the assembly mutual of the collecting plate and the collecting box.

In a known method of this type, the pressing operation performs a pre-compression of the seal, which is then further compressed during the crimping operation.

In known heat exchangers of the aforementioned type, the seal between the manifold plate and the manifold box is ensured by the periphery of the seal, which is received in a peripheral groove of the plate collector, which forms a sort of gutter. This groove also receives the peripheral rim (or heel) of the manifold, against which the crimping means come to bear. The latter can be produced for example in the form of legs folded against the edge of the manifold.

The presence of this peripheral groove has hitherto been mandatory to allow both to house the periphery of the seal as well as the rim of the manifold, and to provide a maintenance of this rim during the operation of crimping. Indeed, without the presence of this groove, the peripheral rim of the manifold would tend to move inward under the effect of significant pressures which are exerted during the crimping operation. In other words, this would result in a deformation and an approximation of the sides which the manifold comprises.

This groove, which surrounds a generally flat bottom of the header plate increases the size, especially the width, of the heat exchanger. Indeed, the size of the collecting plate itself is significantly greater than that of the beam, which is usually defined by the fins.

However, in current vehicles, the space allocated to equipment is more and more limited and it therefore appears necessary to reduce the size of the heat exchangers, while maintaining comparable thermal performance.

It is therefore an object of the invention to provide a solution to this problem.

To this end, the invention provides a method of assembling a collecting plate and a collecting box of a heat exchanger, of the type defined in the introduction, which further comprises an operation for holding opposite sides of the box. collector to maintain a spacing substantially constant between these sides and prevent them from approaching each other, especially during the crimping operation.

Because opposite sides of the manifold are maintained with a substantially constant spacing, one can use a manifold plate having a flat bottom and devoid of a peripheral groove which, until now, was necessary to receive the peripheral edge. This allows the use of a collector plate of reduced size compared to known collector plates, provided with a peripheral groove.

Advantageously, the holding operation is exerted on sections of the peripheral rim of the manifold which are adjacent to the opposite sides of the manifold.

As a variant, this operation can be carried out directly on the opposite sides of the manifold.

When the pressing operation is carried out by pressing means capable of acting on the peripheral rim of the manifold, the holding operation is advantageously carried out by means of the pressing means.

In this case, it is preferable that the holding operation is exerted by form cooperation between the pressing means and the peripheral rim of the manifold.

The pressing means advantageously comprise spouts suitable for penetrating a groove provided on an upper face of the peripheral rim.

As a variant, the pressing means comprise claws suitable for penetrating an upper face of the peripheral rim.

In another aspect, the invention relates to a heat exchanger as can be obtained by the process defined above and comprising at least one collector plate and a manifold capable of being assembled together, the manifold being provided externally with support surfaces usable during the holding operation to maintain a substantially constant spacing between the sides of the manifold.

In a preferred embodiment of the invention, the bearing surfaces are provided on an upper face of the peripheral rim of the manifold.

When the assembly of the manifold plate and the manifold box is carried out by crimping tabs folded against the upper face of the peripheral rim of the manifold box, the bearing surfaces are then arranged in regions of the upper face which are between the crimp tabs.

These bearing surfaces may include a continuous or interrupted groove, or even imprints resulting from the action of holding claws.

According to another characteristic of the invention, the collector plate comprises a substantially flat bottom and devoid of a peripheral groove for the complete reception of the peripheral rim of the collector box.

In general, the invention applies to heat exchangers which can be either of the type with mechanical assembly, or of the brazed type. In the first case, the ends of the tubes are received in the collars of the collector plate with insertion of corresponding collars forming part of the seal. In the second case, the ends of the tubes are received directly in the collars of the collector plate and are brazed to the latter.

The invention applies to heat exchangers which may include one or more rows of tubes. It should be understood that the invention also extends to the heat exchangers defined above and obtained by analogous or equivalent methods.

In the description which follows, given solely by way of example, reference is made to the appended drawings, in which:

- Figure 1 is a partial cross-sectional view of a heat exchanger according to a first embodiment of the invention, comprising a manifold plate and a manifold assembled by crimping;

- Figure 2 is a sectional view on a reduced scale, similar to Figure 1, showing the heat exchanger before pressing and crimping;

- Figure 3 is a sectional view, similar to Figure 2 showing the heat exchanger during pressing and before crimping;

- Figure 4 is a partial sectional view of a heat exchanger according to a second embodiment of the invention, before assembly and pressing; and

- Figure 5 is a sectional view similar to Figure 4 after pressing and crimping.

The heat exchanger shown in Figure 1 is, in the example, intended to be part of a motor vehicle to constitute either a radiator for cooling the engine, or a radiator for heating the passenger compartment. This exchanger comprises a bundle 10 formed from a multiplicity of tubes 12, for example made of aluminum, having a cross section of chosen shape, for example oval. These tubes are arranged parallel to each other in a single row and they pass through a multiplicity of fins 14 formed by rectangular metal plates which are parallel to each other. Each tube 12 has a free end 16 mechanically assembled to a collecting plate 18, also called "collector". The tubes 12, the fins 14 and the manifold plate 18 are made of a metallic material based on aluminum.

The collector plate 18 comprises a flat core 20 of generally rectangular shape in which holes 22 are formed having an internal section of shape homologous to that of the tubes. Each of the holes 22 is surrounded by a collar 24 directed towards the side of the fins 14. The core 20 of the collector plate 18 is folded around its periphery to form crimping tabs 26, resembling teeth or slots, and capable of '' be folded down during a crimping operation.

The collector plate 18 receives, on its face opposite to the bundle, a compressible seal 28 which comprises a core 30 suitable for pressing against the core 20 of the collector plate. This core 30 is planar and it has a periphery 32 which extends to the inner periphery of the collecting plate 18, as delimited by the crimping tabs 26. The seal 28, which is advantageously made of elastomer, is formed with a multiplicity of collars 34 provided in correspondence with the collars 24 of the collector plate. Each of the collars 34 is suitable for sealing between the end 16 of a tube and the corresponding collar 24 of the collector plate. This sealing is ensured in a known manner by expanding the end 16 of each tube by passing an appropriate tool, also called an "olive". Each of the collars 34 thus comprises a bead 36 which protrudes from the collar 24, on the side of the fins 14.

The heat exchanger of Figures 1 to 3 further comprises a protective plate 37 which has a general U-shaped profile and which is adapted to bear between the core 20 of the manifold plate and the first fin of the bundle. The plate 37 protects the beads 36 of the seal as well as the ends of the tubes in the region of the fillers. lets. It also guarantees a chosen value difference between the first fin of the beam and the collector plate.

In addition, the heat exchanger comprises a collecting box 38, advantageously made by molding a plastic material and having an open face of generally rectangular shape delimited by a peripheral rim 40, also called "heel" or "foot" . The peripheral flange 40 comprises a bottom face 42 capable of coming into contact with the seal, this face being provided with a peripheral rib 44, projecting, and suitable for ensuring the compression of the seal, as will be seen more far.

The rim 40 further comprises an upper face 46 in which a groove 48 is formed which preferably extends over the entire periphery of the peripheral rim 40 and which can be produced continuously or discontinuously.

The manifold 38 has two opposite sides 50, also called longitudinal sides, which are connected with the peripheral flange 40 and with an upper part 52 in the form of a dome.

To ensure the assembly of the heat exchanger of FIG. 1, one begins first by assembling the bundle 10 to the collector plate 18 according to a technique in itself known, which is not part of the invention .

Then, as shown in FIG. 2, the peripheral flange 40 of the manifold 38 is placed opposite the periphery 32 of the seal 28, the crimping tabs 26 being in an initial position that is not folded down. Then a pressing operation is carried out using a pressing tool 54 which comprises a plate 56 provided with an opening 58 capable of providing passage to the manifold 18. The pressing tool 54 is provided, on the periphery of the opening 58, a plurality of spaced spouts 60 which are capable of coming to bear against bearing surfaces 62 formed on the upper face 46 of the peripheral rim 40. These spouts are provided so as to come into abutment against the upper face 46 of the rim in regions of this upper face which are included between the crimping lugs, in order to provide support by form cooperation.

To carry out the pressing operation, it suffices to move the pressing tool 54 in the direction of the arrows FI by suitable mechanical means, to thus achieve a pre-compression of the seal. During this pre-compression, the periphery 32 of the seal 28 is compressed and the rib 44 of the flange 40 comes into contact with the core of the seal.

Then, while maintaining the compression of the seal by the pressing tool 54, a crimping operation is carried out by an appropriate crimping tool (not shown). This crimping action is carried out on the tabs 26 as shown by the arrows F2 (FIG. 3), which makes it possible to fold the tabs 26, the ends of which are housed in the groove 48 of the upper face

46. However, as during this operation, the pressing action is maintained, the sides 50 of the manifold

38 are kept at a substantially constant distance and therefore do not risk approaching each other under the action of significant forces exerted by the crimping tool.

In the embodiment of Figures 1 to 3, the holding action is exerted, by means of the spouts 60 of the pressing tool, on two sections 64 of the peripheral flange 40 (Figure 3) which are adjacent respectively on both sides 50.

Because the header plate 18 of the heat exchanger is devoid of groove for receiving the peripheral rim of the header box, it has dimensions, in particular a width L (FIG. 1), smaller than those of the header plates of the heat exchangers known heat, with equal thermal performance elsewhere.

In the embodiment of Figures 4 and 5, there is an arrangement similar to that of Figures 1 to 3. The main difference lies in the fact that the peripheral flange 40 of the manifold 38 has an upper face 66 which is substantially planar . Furthermore, the crimping tool 54 includes claws 68 which replace the spouts 60 of the previous embodiment. These claws are intended to come into the material of the peripheral rim during the pressing operation, which ensures lateral maintenance of the longitudinal sections of the peripheral rim, and therefore of the sides 50 of the manifold. As a result, when the pressing and crimping operation is completed, imprints, resulting from the action of the claws, remain on the upper face 66, in regions included between the crimping teeth.

Furthermore, in the embodiment of Figures 4 and 5, the bottom 20 of the collector plate 18, has a small peripheral groove 70 which is intended simply to receive the periphery 32 of the seal 28, and not to receive the complete peripheral rim of the manifold. In fact, this groove could be omitted to produce a flat bottom as in the embodiment of FIGS. 1 to 3.

In Figure 4, the peripheral edge of the manifold is shown at a distance from the seal, and here is the pressing tool 54 which moves the manifold to bring it closer to the seal. As in the previous embodiment, the compression of the seal is ensured by the pressing tool 54 (FIG. 5) and the crimping is carried out while the compression is maintained. Of course, the invention is not limited to the embodiments described above by way of examples and extends to other alternative embodiments.

In particular, the flank holding operation 50 could be carried out in other ways, for example by acting directly on the flanks 50 by pins or the like which would engage in protuberances, of the "eyelet" or "ears" type. ", made by molding with the sides 50 of the manifold.

In addition, although the invention has been described with reference to a heat exchanger with a single row of tubes, it can be applied to heat exchangers with several rows of tubes.

Furthermore, the invention is not limited to heat exchangers of the mechanical assembly type, and it can also be applied to heat exchangers of the brazed type, in which the bundle tubes are brazed directly to the plate. collector.

Claims

claims 1. Method for assembling a collecting plate (18) and a collecting box (38) of a heat exchanger, in particular of a motor vehicle, in which the collecting plate is provided with crimping means (26) able to come into abutment against a peripheral rim (40) of the manifold by compressing a seal (28), the method comprising a pressing operation exerted on the manifold to at least partially compress the seal, and a crimping operation exerted on the crimping means to effect mutual assembly of the manifold plate and the manifold , characterized in that it further comprises an operation for holding opposite sides (50) of the manifold (38) in order to maintain a substantially constant spacing between these sides and preventing them from approaching one another, in particular during the crimping operation. 2. Method according to claim 1, characterized in that the holding operation is exerted on sections (64) of the peripheral rim (40) of the manifold box (38) which are adjacent to the opposite sides (50) of the box collector. 3. Method according to claim 1, characterized in that the holding operation is exerted directly on the opposite sides (50) of the manifold (38). 4. Method according to one of claims 1 and 2, wherein the pressing operation is carried out by pressing means (54) adapted to act on the peripheral edge (40) of the manifold, characterized in that the holding operation is exerted via the pressing means. 5. Method according to claim 4, characterized in that the holding operation is exerted by form cooperation between the pressing means (54) and the peripheral flange (40) of the manifold (38). 6. Method according to claim 5, characterized in that the pressing means (54) comprise nozzles (60) adapted to penetrate a groove (48) provided on an upper face (46) of the peripheral rim (40). 7. Method according to claim 5, characterized in that the pressing means (54) comprise claws (68) adapted to penetrate into an upper face (66) of the peripheral rim (40). 8. Heat exchanger as can be obtained by the method of one of claims 1 to 7, comprising at least one manifold plate and one manifold assembled together, the manifold box (38) being provided externally with bearing surfaces (62) which can be used during the holding operation to maintain a substantially constant spacing between the sides (50) of the manifold. 9. Heat exchanger according to claim 8, characterized in that the bearing surfaces (62) are provided on an upper face (46; 66) of the peripheral flange (40) of the manifold (38). 10. Heat exchanger according to claim 9, wherein the manifold plate (18) and the manifold box (38) are assembled by crimping lugs (26) folded against the upper face (46) of the peripheral flange (40) of the manifold, characterized in that the bearing surfaces (62) are arranged in regions of the upper face (46; 66) which are included between the crimping lugs (26). 11. Heat exchanger according to one of claims 9 and 10, characterized in that the bearing surfaces comprise a groove (48) continuous or interrupted. 12. Heat exchanger according to one of claims 9 and 10, characterized in that the bearing surfaces include imprints resulting from the action of holding claws (68). 13. Heat exchanger according to one of claims 8 to 12, characterized in that the collector plate (18) comprises a bottom (20) substantially flat and devoid of a peripheral groove for the complete reception of the peripheral rim of the collector box.