EP0256913B2 - Heat exchanger having a tube bundle and plastic header boxes - Google Patents

Description

The invention relates to a heat exchanger with bundles of plastic tubes and fluid boxes, in particular a radiator for the cooling of a truck engine.

GB-A-20 90 958, in accordance with the preamble of claim 1, is known from heat exchangers for motor vehicles of the type comprising a bundle of parallel tubes and, at one or two ends thereof, a plastic fluid box molded in one piece with a bottom closing one of its ends and a manifold wall, the ends of the tubes entering the fluid box in a liquid-tight manner through holes in the manifold , while said bottom extends obliquely so that the length of the fluid box is less in its longitudinal zone opposite to the manifold than in the longitudinal zone of said manifold, and further comprising at least, at one end of the fluid box, extending parallel to the tubes in a region offset in the longitudinal direction of the tubes and towards the median transverse plane thereof with respect to the collect eur, on the one hand, a base molded with the plastic fluid box and, on the other hand, a mounting crosspiece used to reinforce the structure of the heat exchanger and to mount it on the vehicle, said crossmember being fixed to the base while leaning on it by means of a back which it has for this purpose.

In known exchangers of this type, on the one hand, the fluid box has a peripheral rim or edge, which increases its size, and, on the other hand, the base and the associated end of the cross member. assembly described in Figures 4 and 5 of the aforementioned document, have a complicated shape.

In fact, the base is in the form of a molding and a shutter made in the cross member is folded so that it matches the molding. In addition, the cross-member forms a spacer between the collectors of the upper and lower fluid boxes to keep the distance between them constant.

In addition, the cross member is engaged, before mounting of the fluid boxes, in notches that have the fins of the tube bundle.

In document FR-A-2 472 734, a heat exchanger is described with a flanged fluid box provided with a metal manifold and a water box with a flange on which are fixed, on the one hand, the collector and, on the other hand, intermediate parts used for mounting the cross member, the fixing of said intermediate parts being effected by claws or legs folded over the edge of the water box. These intermediate parts have ribs, in the shape of a right triangle, which strengthen the connection between the mounting cross member and the fluid box.

As a result, the assembly of the heat exchanger is complicated since it is necessary to fix the intermediate parts between each fluid box and each crosspiece.

In addition, the fluid boxes must be of a very specific type in which the collector is an independent box which has just been attached and fixed on the edge or peripheral edge of the water box.

In addition, in known heat exchangers of this type, the bottoms which form the ends of the fluid boxes extend perpendicular to the longitudinal direction of the fluid box, that is to say parallel to the longitudinal direction of the tubes.

It follows that the size of the heat exchanger in the plane defined by the longitudinal direction of the tubes and the longitudinal direction of the fluid boxes is that of a rectangle with a flange.

Consequently, the width of the exchanger, that is to say its dimension in the longitudinal direction of the fluid boxes, remains substantially constant over its entire height, that is to say over its extent in the longitudinal direction tubes.

It is advantageous, in certain cases, to more easily accommodate the radiator in the vehicle body, to reduce its width to at least one of its ends, in particular its upper end, without modifying the width of the bundle of tubes and the length. - gueurassociée of the collector which have an influence on the heat exchange capacity.

It has been proposed, in particular in document EP-A-0 115 795 or EP-A-0 170 952, describing an arrangement with a flanged fluid box provided with a plastic water box, with a flange, mounted to seal on a metal manifold, that the mounting crosspieces are provided at their ends with large wings which enclose the end of the water box by being fixed and maintained thereon.

This arrangement has the drawback, on the one hand, of requiring special and complex arrangements both at the level of the water box and at the level of the crosspieces and, on the other hand, of limiting the possibility of reducing the width of the 'exchanger.

The object of the invention is to provide a simpler construction between the fluid box and the mounting cross member (s) allowing particularly easy mounting and a compact installation.

Another object of the invention is to provide a heat exchanger structure allowing a reduction in local width.

These objects are achieved according to the invention, in a heat exchanger of the type described in the aforementioned document GB-A-20 90 958, in that the internal face of the back of the mounting crosspiece is supported on ribs belonging to the base and defining, by their vertices, a support plane for the cross member, in that the connection between the mounting cross member and the fluid box is reinforced by reinforcing ribs, in that said ribs are molded with the fluid box and connect the base to the fluid box, in that each reinforcing rib has the shape of a right triangle of which one side of the right angle coincides with a vertical side of the base and the other of which corresponds to a longitudinal part of the manifold, in that said fluid box has no rim being tubular with a tubular wall including a manifold-shaped portion, in that the base extends directly to the right of said end of the fluid box, and in that the two ends of the fluid box are chamfered by oblique bottoms so that the length of the fluid box is less in its longitudinal region opposite to the manifold than in the longitudinal area of said manifold.

Because the bases are molded with the fluid box, it is not necessary to provide an intermediate piece between the fluid box and the crosspieces.

As a result, the assembly of the heat exchanger is much simpler.

The base plane of the base, defined by the ribs, makes it possible to simplify the base and the mounting cross member compared to those described in FIGS. 4 and 5 of document GB-A-20 90 958.

In addition, the rigidity of the heat exchanger is increased because the bases and the reinforcing ribs are in one piece with the fluid box comprising at least one tubular section molded in one piece.

In addition, the fact that the fluid box has no lateral rim makes it possible to reduce the width of the heat exchanger at at least one of its ends, in particular its upper end.

The fact that the base extends directly to the right of said end of the fluid box also makes it possible to reduce the width of the heat exchanger at at least one of its ends.

The offset of the base, relative to the tubular wall, in the direction of the median transverse plane of the tubes, allows the radiator to be chamfered by the oblique bottoms, which makes it possible to locally reduce the space requirement in width of the exchanger heat.

In a preferred embodiment of the invention, the base is connected to the fluid box by two parallel ribs.

The invention applies to any plastic fluid box comprising a tubular wall, a portion of which forms the manifold.

In this type of fluid box, one end of the tubular wall, which forms the bottom, is molded, while the other end is open to receive a bottom cover.

The invention can also be applied to fluid boxes in a single section or in two sections.

• - la figure 1 est une vue de face d'un radiateur conforme à l'invention;
• - la figure 2 est une vue en coupe, longitudinale de l'une des sections tubulaires formant la boîte à fluide supérieure du radiateur de la figure 1 ;
• - la figure 3 est une vue en bout de la section tubulaire de la figure 2.

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

• - Figure 1 is a front view of a radiator according to the invention;
• - Figure 2 is a longitudinal sectional view of one of the tubular sections forming the upper fluid box of the radiator of Figure 1;
• FIG. 3 is an end view of the tubular section of FIG. 2.

The radiator shown in Figure 1 has, seen from the front according to Figure 1, the general shape of a rectangle whose sides extend vertically and horizontally. It essentially comprises a bundle of parallel tubes 1 directed vertically and regularly distributed in several rows over the width of the radiator. To simplify the drawing, only two tubes 1 are shown in Figure 1 in the vicinity of one of the vertical edges of the radiator. The ends of the tubes 1 open into fluid boxes, for example water boxes, of generally tubular shape 2-1, 2-2 extending respectively along the upper and lower horizontal sides of the radiator.

Each of the fluid boxes is, in the example, formed of two tubular sections 20 molded from plastic and assembled together by welding. Each tubular section 20 which is molded in one piece has, as shown in Figures 2 and 3, a tubular wall 21, a bottom 22 closing one end of the wall 21, an assembly base 23 extending parallel to the tubes 1 and two reinforcing ribs 24 connecting the base 23 to the tubular wall 21. These two ribs are parallel and have the general shape of a right triangle (Figure 2).

The end 25, opposite the bottom 22, of the tubular wall is open. Two sections 20 are welded to each other by friction through their end faces 26 surrounding the opening 25, thus producing a tubular fluid box closed at its two ends by the oblique bottoms 22.

The tubular wall 21 of each fluid box comprises a flat wall portion 27 forming a manifold, crossed in a liquid-tight manner by the ends of the tubes 1 in a manner known per se. The oblique bottoms 22 are oriented so that the length of the fluid box, that is to say the width of the radiator, decreases from the plane of the manifold towards the part opposite the latter of the tubular wall. 21, that is to say towards the upper or lower end of the radiator. The angles of these are therefore chamfered, which facilitates its accommodation in the vehicle body. The bases 23 of the tubular sections 20 are used to assemble them ci to profiled cross members 3 extending along the vertical sides of the radiator. Each cross member 3 comprises a back 30 forming the corresponding lateral face of the radiator and two wings 31 extending along the main faces thereof. The crosspieces 3 serve to reinforce the structure of the radiator and to mount it on the vehicle by means of lugs 41 and 42 which are fixed to it.

The internal face of the backs 30 rests on horizontal ribs 50 and vertical ribs 51 belonging to the base 23 and defining, by their vertices, a support plane 52 for the sleepers (Figures 2 and 3). The support plane 52 is perpendicular to the longitudinal direction of the fluid boxes, therefore parallel to the longitudinal direction of the tubes 1. Each base 23 is crossed by four holes 53 surrounded by bosses 54 which terminate in the support plane 52 These holes 53 and corresponding holes made in the back of the crosspieces allow the latter to be assembled to the fluid boxes by assembly elements 6 such as rivets or screws for example.

To allow the radiator to be chamfered by the oblique bottoms 22, each base 23 is offset, relative to the tubular wall 21, in the direction of the median transverse plane M of the tubes 1 (Figure 1). More precisely, the base is on the side of the plane M with respect to the plane of the manifold 27. Two ribs 24 extending substantially along the two main faces of the radiator respectively ensure a rigid connection from the base to the tubular wall 21. Each rib 24 has the shape of a right triangle of which one side of the right angle coincides with a vertical side of the base and the other of which corresponds to a part of the longitudinal side of the manifold. The hypotenuse of the right triangle forms a free side of the rib.

The fluid boxes 2-1 and 2-2 are linked to each other in their central region by two tie rods 55 passing through holes made in bosses 56 provided on the tubular walls of the tubular sections 20. These tie rods 55 support the longitudinal forces due to the bending tendency of the fluid boxes when the radiator is full of pressurized fluid, and thus prevent tearing forces being exerted on the welds of the ends of the tubular sections. One of the ends 57 of each tie rod is folded at a right angle and rests on a boss 56, while the opposite end 58 is threaded and cooperates with a nut 59 which is tightened on another boss 56.

Although the invention has been described with particular reference to a heat exchanger comprising two fluid boxes each formed from two tubular sections connected end to end, it applies to heat exchangers in which each fluid box is formed from a single tubular section.

It also applies to heat exchangers comprising one or two crosspieces.

In all cases, the mounting cross member extends parallel to the tubes 1 and is fixed to one end of the fluid box in an offset region, in the longitudinal direction of the tubes 1 and towards the median transverse plane M thereof. , with respect to the collector 27.

This cross member 3 is on the side of the plane M relative to the plane of the manifold 27 (Figure 1).

The base extends directly to the right of the relevant end of the fluid box (Figures 1 and 2).

Claims (3)

1. A heat exchanger for a motor vehicle, of the type comprising a bundle of parallel tubes (1) and, at one or two ends of the latter, a fluid manifold (2-1, 2-2) of plastics material, moulded in one piece with a base (22) closing one of its ends and a wall defining a collector (27), with the ends of the tubes penetrating into the fluid manifold in a liquid-tight manner through holes formed in the collector (27), while the said base (22) extends obliquely in such a way that the length of the fluid manifold (2-1, 2-2) is smaller in its longitudinal zone opposite to the collector (27) than in the longitudinal zone of the said collector, and further including, at least at the level of one end of the fluid manifold (2-1, 2-2) and extending parallel to the tubes (1) in a region which is offset with respect to the collector (27) in the longitudinal direction of the tubes (1) and towards the transverse median plane (M) of the latter, firstly, a base (23) moulded integrally with the fluid manifold (2-1, 2-2) of plastics material and, secondly, a mounting beam (3) which reinforces the structure of the heat exchanger and mounts the latter on the vehicle, the said beam (3) being secured to the base (23) while engaging it through a back portion (30) with which it is formed for this purpose, characterised in that the internal face of the back portion (30) of the mounting beam (3) is engaged on ribs (50, 51) of the base (23), the summits of the ribs defining an engagement plane (52) for the beam (3), and in that the connection between the mounting beam (3) and the fluid manifold (2-1, 2-2) is reinforced by reinforcing ribs (24), in that the said ribs (24) are formed integrally by moulding with the fluid manifold (2-1, 2-2) and join the base (23) to the fluid manifold (2-1,2-2), in that each reinforcing rib (24) is in the form of a right angled triangle, in which one side of the right angle is coincident with one vertical side of the base (23), with the other one corresponding to a longitudinal portion of the collector (27), in that the fluid manifold (2-1, 2-2) has no flange and is of tubularform having a tubularwall (21), a portion (27) of which defines the collector, in that the base (23) extends directly in line with the said end (22) of the fluid manifold (2-1, 2-2), and in that the two ends of the fluid manifold (2-1, 2-2) are chamfered with oblique base portions (22), in such a way that the length of the fluid manifold (2-1, 2-2) is smaller in its longitudinal zone opposite to the collector (27) than in the longitudinal zone of the said collector (27).

2. A heat exchanger according to Claim 1, characterised in that the base (23) is joined to the fluid manifold (2-1, 2-2) through two parallel reinforcing ribs (24).

3. A heat exchanger according to Claim 1 or Claim 2, characterised in that the fluid manifold (2-1,2-2) has two tubular sections (20) having at least one open end and assembled together by welding.

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