FR2935474A1 - FIXING DEVICE FOR A HEAT EXCHANGER WITH FINS, IN PARTICULAR FOR MOTOR VEHICLES - Google Patents

Abstract

An attachment device (20) for a heat exchanger having a fin block (18) having two opposite major faces (24, 26) connected by an end face (28), and wherein two main faces have respective grooves (30, 32) formed by notches of the fins. The device is a generally U-shaped clip having two legs (34, 36) joined by a bottom (38) and arranged to cap the block of blades (18) in an engagement position in which the two legs (34) , 36) bear respectively against the two main faces (24, 26) of the fin block (18) and the bottom (38) against the end face (28) of the fin block, the two branches ( 34, 36) having respective lugs (40, 42) projecting inwardly and engageable in the respective grooves (30, 32) to secure the device to the clapper block by snapping. The fixing device makes it possible to attach an accessory to a heat exchanger.

Description

FIELD OF THE INVENTION The invention relates to the field of heat exchangers, in particular for motor vehicles.

It relates more particularly to a fixing device for a heat exchanger of the flat fin type. Heat exchangers of the mechanical assembly type are already known, equipped with collecting boxes, for example made of plastic, and whose bundle consists of tubes crimped onto a block or pack of fins. A heat exchanger, in particular for motor vehicles, may be equipped with one or more accessories, for example a motor-fan unit, a motorcycle fan unit skirt, an anti-vibration tab, etc.

A known solution is to fix this accessory on at least one of the collector boxes of the heat exchanger.

It is also known to fix this accessory directly on the beam, that is to say on the finned block. Thus, a known solution, as taught for example by the publication FR 2 730 009, consists in fixing a motor-fan unit directly on the beam by means of fixing screws which pass through the beam passing between the tubes and taking into account sandwich the fins.

Since these screws must pass between the tubes, their pitch must not fall below a minimum value, generally of the order of 12 mm, in order not to risk damaging the tubes during the installation of the screws. and associated washers, but especially when tightening. Another known solution is to use a fastening device consisting of two parts which snap or snap between them by capping the fin block and tighten the fins by deforming them. This known solution also has disadvantages. First, the fixing device requires the assembly of two different parts. Then, the mounting of this device causes a deformation of the fins which is at the expense of thermal performance of the exchanger.

The object of the invention is in particular to overcome the aforementioned drawbacks.

It proposes for this purpose a fixing device for a heat exchanger having a fin block having two opposite main faces connected by an end face and wherein the two main faces have respective grooves formed by notches of the fins.

According to the invention, this fixing device is made in the form of a generally U-shaped clip having two branches joined by a bottom and arranged to cap the fin block in an engagement position in which the two branches respectively bear against the two main faces of the fin block and the bottom against the end face of the fin block, the two branches having respective lugs protruding inwards and adapted to engage in the respective grooves for holding the device on the blade block by snapping.

The invention thus takes advantage of the existence of notches on flat fins which together form grooves.

It is known in fact to produce fins whose two ends are provided each time with a pair of opposite notches which have the function of allowing alignment or referencing of the fins during assembly of the heat exchanger bundle. .

Therefore, when these fins are aligned and traversed by the tubes, the notches define opposite grooves and it is these grooves that will serve to maintain the fastener of the invention.

In the invention, the device has the shape of a U-shaped clamp and it comes to cap one end of the beam. The presence of pins on the two branches ensures a commitment thereof in the grooves formed by the notches of the fins to maintain the device on the fin block. As the grooves extend over the entire length of the fin block, in a direction parallel to the tubes, it allows to implant the fastener at a selected position along the length of the fin block.

This solution is advantageous because it allows the device to be fixed even in heat exchangers having a very small pitch between the tubes.

In addition, the mounting of the fixing device does not cause deformation of the fins.

In an advantageous embodiment of the invention, one of the lugs and a rigid lug carried by a first branch, while the other is a flexible lug carried by a second branch and resiliently biased towards the inside of the gripper. U. 35 Thus, during the engagement of the device, the rigid pin engages in one of the grooves, while the flexible lug deforms elastically by moving apart and then returns to its initial position to come s engage in the other groove, which causes immobilization of the device in a selected position along the beam, that is to say the block of fins.

In another aspect, the invention relates to a heat exchanger having a fin block having two opposite major faces connected by an end face and wherein the two main faces have respective grooves formed by notches of the fins.

This heat exchanger is provided with at least one fixing device according to the invention and an accessory fixed by this or these fixing devices.

In the detailed description which follows, given by way of example only, reference is made to the accompanying drawings, in which: FIG. 1 is a partial front view of a heat exchanger whose bundle comprises a block of heat; fins traversed by tubes, this heat exchanger being provided with two fastening devices according to the invention which serve to fix an accessory;

- Figure 2 is a partial cross-sectional view of one end of a fin block equipped with a fastening device according to the invention in its engagement position;

- Figures 3 and 4 are two perspective views showing the fixing device in its engagement position;

FIG. 5 is a view similar to FIG. 2 showing the fixing device during assembly; and - Figure 6 is a view similar to Figure 5, once the fastener assembled in its engagement position.

FIG. 1 represents a mechanical assembly type heat exchanger 10 which, in the example, is a cooling radiator of a motor vehicle engine. The heat exchanger 10 comprises two opposed manifolds 12, for example made of plastic material, between which a bundle 14 consists of tubes 18 parallel to one another, which open at their respective ends into the manifolds 12. The bundle 14 further comprises a block of fins 18. The tubes pass through respective openings of the fins and are crimped on these fins in a known manner. The fins here are planar fins of generally rectangular shape made of thin sheets of a metal alloy, usually an aluminum-based alloy.

As seen in Figure 1, two fasteners 20 according to the invention cap the beam to serve as attachment to an accessory 22, for example, a skirt of a motor-fan unit. This accessory 22 can be attached to the other end of the beam by one or more similar fasteners, or other means.

Referring now to FIG. 2, the fin block 18 has two opposite main faces 24 and 26, parallel to each other, and connected by an end face 28. The main faces 24 and 26 have respective grooves 30 and 32 formed by notches of the fins. These notches are made in a manner known per se, to form pins for referencing or aligning the fins during the assembly process of the beam. As mentioned above, the invention takes advantage of the existence of these notches by assigning them a new function.

The fastening device 20 is in the form of a generally U-shaped clip, having two branches 34 and 36 joined together by a bottom 38. This clip is arranged to cap the block of fins 18 in a position d engagement in which the branches 34 and 36 respectively bear against the main faces 24 and 26 of the fin block. In this engagement position, the bottom 38 is pressed against the end face 28 of the fin block.

The device 20 is held in this engagement position by virtue of two lugs 40 and 42 projecting inwards from the U-shape and able to engage in the respective grooves 30 and 32 to ensure snap-fastening or clipping retention. .

As will be seen below, the lug 40 is a rigid lug carried by a first U-shaped branch namely the branch 36, while the other lug is a flexible lug 42 carried by a second branch, namely the branch 36 , and this lug is resiliently biased towards the inside of the U-clamp.

The rigid pin 40 extends on the inner side of the first branch near a connection zone 44 of the branch 34 with the bottom 38 and this lug is made in one piece with the first branch, without any possibility of movement relative to to this one.

The flexible lug 42 extends on the inner side of the branch 36 near another connection zone 46 of the branch 36 with the bottom 38. This flexible lug 42 is carried by a deformable tongue 48 (FIGS. and 6) cut into the thickness of the branch 36. This tongue is biased elastically on the inside of the second branch.

The fixing device 20 is made in one piece, advantageously by molding a plastic material, preferably a rigid or semi-rigid plastic material. An example of a suitable material is a polyamide filled with glass fibers.

The device 20 has dimensions adapted to those of the fin block, that is to say that the distance between the two branches must be a function of the thickness of the beam, therefore the width of the end face 28. Also, the lugs 40 and 42 must be adapted to the dimensions of the notches, and the position of these lugs, relative to the bottom 38, takes into account the distance of the notches 30 and 32 with respect to the end face 28 of the block of fins.

The deformable tongue 48 is cut into the thickness of the wafer 36 as best seen in FIGS. 4, 5 and 6. This deformable tongue 48 is delimited by a U-shaped cutout 50 (FIG. 4) having a side end portion 52 is rectilinear and generally parallel to bottom 38. It contributes to delimiting an end of the tongue along which is situated the pin. flexible 42. The two opposite sides 54 of the cut are connected perpendicularly to the end sides 52. They are straight and generally parallel to each other.

These two opposite sides 54 each extend from the side of the end 52 to a deformable edge 56 forming a joint and schematized by a line XX in Figure 4. This deformable edge, which is parallel to the side end 52 and extends away from this end side thus forms a hinge. The end side 52 is located near the bottom 38 of the device, while the deformable hinge edge 56 extends in an intermediate region of the branch 36 between the connection zone 46 and the end of the branch 36.

The branches 34 and 36 have respective free ends 58 and 60 which delimit an open face of the U-shaped gripper, as can be seen more particularly in FIGS. 2, 5 and 6.

In the exemplary embodiment, the lugs 40 and 42 each have an asymmetrical tooth-like profile. Thus, the lug 42 has an inclined face 62 directed towards the opening of the U-shaped clamp, as defined by its free ends, and by a retaining face 64 disposed on the bottom side of the U-shaped clamp (FIG. 2). The lug 42 has a similar shape.

The branches 34 and 36 have specific shapes. They have first portions 66 and 68, respectively, which connect perpendicular to the bottom 38 and which are therefore substantially parallel to one another. These first two portions are extended by respective second portions 70 and 72 which converge towards one another and terminate in the free ends 58 and 60. As these second portions 70, 72 converge towards one another, towards the free ends, that is to say towards the opening of the clamp, they contribute to the clamping of the clamp on the block of fins.

Note that the free ends 58 and 60 are bent in opposite directions to facilitate engagement of the clamp on the fin block. Furthermore, the parts 70 and 72 are internally provided with support pads 74 and 76 which are best seen in Figures 2 and 6. These pads are arranged vis-à-vis and located near the free ends 58 and 60. Their function is to prevent inadvertent movement of the device parallel to the direction of the tubes of the beam. They are advantageously provided with a striated structure to facilitate cooperation with the edges of the fins.

In the exemplary embodiment shown, the device comprises a fastening tab 78 attached externally to the U-clamp. Here, this lug projects from the branch 34 at the connection zone 44. This lug is also provided with an opening 80 of generally oblong shape that can be used to pass a fastening screw or the like.

The device may be provided with one or more fastening tabs. The structure and location of the latter may vary depending on the accessory that must be attached to the heat exchanger.

To assemble the fixing device, proceed as shown in Figure 5. It engages the open face of the clamp so as to cap the beam. During the engagement, the rigid pin 40 is first slid along the main face 24 in the region of this face between the end face 28 and the notch 30. Simultaneously, the flexible pin 42 is slid along the main face 26 in the region of this face between the end face 28 and the notch 32. In doing so, the flexible lug deviates as shown by the arrow F1 in FIGS. 5. Indeed, in the rest position, the distance between the two lugs is less than the width of the end face 28. By continuing the movement, the lug 40 engages in the groove 30, while that the lug 42 is engaged in the groove 32 by elastic effect of the tongue 48 as shown by the arrow F2 in Figure 6.

In the fully engaged position, the two lugs are engaged in the respective grooves and the device is immobilized. The presence of the pads 74 and 76 prevents inadvertent sliding of the device in a direction parallel to that of the tubes of the beam.

The fact of having a fixed lug and a flexible lug, so deformable, avoids a separation of the branches during the engagement movement.

Indeed, if the two lugs were rigid and integral branches, the latter should deviate significantly to allow commitment with the risk that these two branches lose an elasticity effect.

The invention is capable of numerous variants, in particular with regard to the shapes and dimensions of the device which will be adapted to those of the block of fins considered.

As already indicated, the device may comprise one or more fixing lugs adapted to the attachment of a particular accessory.

A preferred application of the invention is that of motor vehicle cooling radiators. The device can then be used to attach a motor-fan unit, a motor-fan unit skirt, an anti-vibration tab, etc.

Claims (14)

Revendications1. Fastening device for a heat exchanger (10) having a fin block (18) having two opposite main faces (24,26) connected by an end face (28) and in which the two main faces have grooves respective ones (30, 32) formed by notches of the fins, characterized in that the fastening device (20) is in the form of a generally U-shaped clip having two legs (34, 36) joined by a bottom (38) and arranged to cap the fin block (18) in an engagement position in which the two legs (34, 36) bear respectively against the two main faces (24, 26) of the fin block (18) and the bottom (38) against the end face (28) of the fin block, the two legs (34, 36) having respective lugs (40, 42) projecting inwards and adapted to engage in the respective grooves (30, 32) to maintain the device on the block of vanes by snap-fastening e. 2. Device according to claim 1, characterized in that one of the lugs is a rigid lug (40) carried by a first leg (34), while the other is a flexible lug (42) carried by a second leg (36) and elastically urged towards the inside of the U-clamp. 3. Device according to claim 2, characterized in that the rigid pin (40) extends on the inner side of the first leg (34) near a connection zone (44) of said first leg (34). with the bottom (38), the rigid pin (40) being integral with the first leg (34). 4. Device according to one of claims 2 and 3, characterized in that the flexible lug (42) extends on the inner side of the second leg (36) near a zone 11de connection (46) of said second leg (36) with the bottom (38), the flexible pin (42) being carried by a deformable tongue (48) cut into the thickness of the second leg (36) and resiliently biased on the inner side of the second leg . 5. Device according to claim 4, characterized in that the deformable tongue (48) is delimited by a U-shaped cutout (50) having an end side (52) adjacent to the flexible lug (42) and two opposite sides (54) each extending from said end side (52) to a deformable hinge edge (56) extending opposite the end side (52). 6. Device according to claim 5, characterized in that the deformable edge (56) forming a hinge extends in an intermediate region of the second leg (36) between the connection zone (46) and a free edge (60) of the second branch (36). 7. Device according to one of claims 1 to 6, characterized in that the lugs (40, 42) each have an asymmetric tooth-shaped profile delimited by an inclined face (62) directed towards the opening of the gripper. U and a retaining face (64) on the bottom side of the U-shaped clamp. 8. Device according to one of claims 1 to 7, characterized in that the legs (34, 36) have respective free ends (58, 60) which define an open face of the U-clamp. 9. Device according to claim 8, characterized in that the legs (34, 36) have first portions (66, 68) which are connected perpendicularly to the bottom (38) and are extended by second parts (70, 72) which are reconvergent towards each other and terminate at their respective free ends (58, 60). 10. Device according to one of claims 8 and 9, characterized in that the respective free ends (58, 60) are bent in opposite directions to facilitate engagement of the clamp on the fin block (18). 11. Device according to one of claims 1 to 10, characterized in that the legs (34, 36) have support pads (74, 76) arranged vis-à-vis and located near free ends respective () of the latter. 12. Device according to one of claims 1 to 11, characterized in that it further comprises at least one bracket (78) externally attached to the clamp U (). 13. Device according to one of claims 1 to 11, characterized in that it is made in one piece by molding a plastic material. 25 A heat exchanger having a fin block (18) having two opposite major faces (24,26) connected by an end face (28) and wherein the two main faces (24,26) have grooves ( 30, 32) respectively formed by notches of the fins, characterized in that it is provided with at least one fastening device (20) according to one of claims 1 to 13, and an accessory (26) fixed by this device (s).