DE19939531C1 - Liquid cooler for internal combustion engines, comprises a plurality of liquid pipes which together with their cooling fins are made of at least one hot-formable plastic foil - Google Patents

Abstract

Liquid cooler, comprises a plurality of liquid pipes which together with their cooling fins are made of at least one hot-formable plastic foil. The liquid cooler for internal combustion engines comprises a plurality of liquid pipes (24) which are located side by side in the same plane within a frame and are provided with cooling fins (30). The latter are distanced from one another and are oriented perpendicular to the pipe axis. Both the pipes and the cooling fins consist of at least one hot-formable plastic foil, with the cooling fins formed of doubled foil sections joined to one another. Also claimed is a method for producing such liquid pipes. It involves folding and welding of the two halves of the hot-formed plastic foil along their contacting edge sections.

Description

The invention relates to a liquid cooler in the Preamble of claim 1 explained type.

At a known type of such a cooler construction, the is not verifiable in printed form, however cylindrical liquid tubes, staggered to each other, threaded into cooling fins made of aluminum strips, which are congruently spaced one behind the other.

To achieve good heat-conducting contact between These then become cooling fins and liquid pipes expanded accordingly and thereby in the breakthroughs of Cooling fins braced.  

A construction variant with better cooling performance sees that Use flat tubes before that are spaced apart and in the same direction in a row in a row aluminum cooling fins retracted and are also clamped in this by widening.

In these embodiments, liquid pipes and To produce cooling fins separately and afterwards cumbersome to assemble.

Another, closest to the subject of the application upcoming cooler construction are those between the Liquid fins provided by cooling fins aluminum bands folded like an accordion.

The liquid tubes are in the form of flat tubes provided, on the flat sides of the aluminum strips support. To ensure good heat flow from the Ensure flat tubes to the cooling fins Flat tubes and aluminum strips in assembled condition in one Post-treat tin bath between these parts Creating thermal bridges.

The individual are also in this construction To produce cooler components for themselves and then assemble, with the subsequent treatment of the composite liquid cooler in the tin bath this  Construction is again significantly more expensive ("MODINE" brochure from Längerer & Reich, Automobiltechnik GmbH, 72124 Pliezhausen).

The invention is therefore based on the object Liquid cooler in a in the preamble of claim 1 explained training, which is essential is easier and cheaper to manufacture.

This object is achieved in a liquid cooler according to the preamble of claim 1 in that the Liquid pipes in the frame in a common level are adjacent to each other that on the liquid pipes outside in the pipe longitudinal direction at a distance from each other Ridge-like, extending transversely to the tube axis direction Cooling fins are provided and that the liquid pipes in addition to cooling fins from at least one thermally formed Plastic film exist, the web wall parts of the as double-walled webs formed cooling fins each other are firmly connected.

In this construction, liquid pipes and Cooling fins only one at a time thermoformed plastic film made cooling element, for its completion no more assembly work are to be carried out and that in comparison to the Forerunner construction only a fraction of that Has weight. In addition, a stock of  specially designed liquid pipes and cooling fins to be completely dispensed with.

The mutual connection of the two, by deep drawing or Embossing formed web wall parts of the cooling fins provides sure that they are not at high working pressures can inflate, so that the liquid cooler as High performance coolers can be used.

The cross-sectional shape of the in the Plastic film molded tube halves after folding the Plastic film a flat tube.

The formed from the liquid pipe and cooling fins Cooling elements can be designed in two parts, for example by being coincident by two and plastic foils welded together longitudinally are formed, in each of which a tube half is molded and cooling fins are also formed.

However, a construction is preferred in which the two pieces of plastic film forming one piece thermoformed and brought to cover by folding and along their two, overlapping each other Longitudinal edge parts are welded together.  

In this case there is only one To trade and manufacture plastic film Liquid pipe only a longitudinal weld perform.  

So when folding the plastic film in it resulting end area of the flat tube whose width remains largely intact, it is proposed that foldable connecting piece between the two film halves to be shaped in such a way that when brought into coincidence Film halves of this connector the shape of an im Cross section of U-shaped longitudinal edge piece of the liquid tube assumes.

A hydrolysis-resistant, high-strength plastic, preferably polyamide (PA 6.6 ), is preferably used as the material for the film. It is useful to reinforce the plastic film in a preferred thickness of 0.30 mm in order to ensure the required strength for the resulting working pressures at higher temperatures with such a film thickness.

Further, preferably used configurations of the Invention are explained in subclaims, wherein In particular, fiber reinforcement of the film is preferred is as explained in claims 12-15.  

The production of liquid pipes according to the invention for Liquid cooler can be done using the following procedure advantageous to accomplish:

In the two halves of a thermally conductive plastic film are cross-sectioned to each other by thermoforming symmetrical, at least one configuration for formation one each of two halves of a liquid tube and in the longitudinal direction of these configurations at a distance from each other, extending transversely to these, a multitude formed by double-walled webs forming cooling fins and at the same time advantageously the web wall parts by Welding, pressure joining or gluing together firmly connected. Then the two film halves are through The folds of the plastic film are aligned so that both configurations complement each other to form a liquid tube. Finally, the free longitudinal edge parts of both Film halves tightly welded together.

In the drawing is an embodiment of a Liquid cooler shown. Show it:

Fig. 1 is a front view of the liquid cooler;

Fig. 2 is a cross section of the liquid cooler, seen along the line II-II of Fig. 1;

. Fig. 3 is a indicated in Figure 2 by a dot-dash circle section, on an enlarged scale;

FIGS. 4a and 4b each show a cross section through a plastic film to form a equipped with cooling fins liquid pipe;

Figure 5 is a plan view of the plastic film, in a shortened representation.

Figs. 6a and 6b each have a cross-section through a made from a film according to Figures 4a 4b liquid pipe or formed.

Fig. 7 is a section along the line VII-VII of Fig. 3; and

Fig. 8 shows the left half of Fig. 4a in a greatly enlarged and partially broken open representation.

The liquid cooler for internal combustion engines shown in FIG. 1 forms, for example, a water cooler; it could just as well be designed as an oil cooler. In a known manner, it has a frame 10 , the lateral frame legs 12 and 14 of which are box-shaped. The frame leg 12 contains a water inflow chamber which can be connected to the cooling water return flow of an internal combustion engine via an inlet connection 16 , while the frame leg 14 contains a water outflow chamber which can be connected to a water pump of the internal combustion engine via a radiator outlet connection 18 .

Both frame legs 12 , 14 are connected to one another in a corner-rigid manner via an upper and a lower frame leg 20 and 22 , which is preferably U-shaped in cross section.

Provided within the frame 10 is a cooling network, which is formed from a multiplicity of individual, for example horizontally extending and superposed, liquid or water pipes 24 . These are connected at the end, as is known per se, to the two chambers of the frame legs 12 , 14 , it being possible for the sealed arrangement of the water pipes 24 of the cooling network on the frame legs 12 , 14 to be achieved by means of casting resin or in another suitable manner.

The construction of the water pipes 24 and their manufacture are explained in detail below:

According to FIGS. 6a and 6b, the water pipes 24 preferably have the cross section of a flat pipe and are provided one above the other in the frame 10 in a common plane such that their flat pipe wall parts 26 and 28 lie one above the other. On both pipe wall parts 26 and 28 , web-like cooling fins 30 are provided on the outside in the longitudinal direction of the pipe at a distance from one another and extend transversely to the pipe axis direction, so that the media flowing through the water cooler are guided in a crossing manner.

The water pipes 24 consist of pressure and hydrolysis-resistant, high-strength plastic, such as PA 6.6 , which are manufactured in two operations from a polyamide film 32, preferably 0.30 mm.

This plastic film 32 is, for example, thermally formed in a deep-drawing tool using a negative pressure and brought into the shape shown in FIGS. 4a and 4b.

The plastic film 32 thus has two film halves 32 a and 32 b, which are flexibly connected to one another via a recess 34 which extends in the longitudinal direction of the film and is reversely channel-like.

The side walls 36 , 38 of this recess 34 continuously expand them outwards and have a partial circular cross-section for this purpose. The bottom 40 of this recess 34 preferably has the shape of a semicircle in cross section.

The cross-sectional shape of the groove-like depression 34 ensures that the plastic film 32 can be folded in such a way that the two film halves 32 a and 32 b come to lie congruently one above the other (see FIGS. 6 a and 6 b) and then the tube wall parts 26 , 28 extend parallel to the longitudinal edge formed by the channel bottom 40 and thus the pipe cross-section is the same over the entire pipe width.

Both film halves 32 a and 32 b each have an outer longitudinal edge piece 42 or 44 , which are stepped in relation to the adjoining tube wall part 26 or 28 in such a way that when the two film halves 32 a and 32 b are congruently assigned, the tube wall parts run parallel to one another. To complete the water pipes 24 , after the plastic film 32 has been folded, its longitudinal edge pieces 42 and 44 are then only to be tightly connected to one another, which can be accomplished, for example, by gluing or folding, but preferably by welding.

The web-like cooling fins 30 have a U-shaped cross section with two web wall parts due to the deep-drawing or, if appropriate, an embossing process. These are connected to one another after the thermal treatment of the polyamide film 32 and thereby stiffened in order to inflate them to the side when the high operating pressure of the liquid cooler prevails in the water pipes, and thus to reduce the cross section of the air ducts 46 defined by the cooling fins 30 and thereby reduce them to avoid the cooling air throughput.

The web-like cooling fins 30 can extend perpendicular to the pipe longitudinal axis. However, it is preferable the slats configuration shown, slightly arcuately curved in Fig. 5, wherein the cooling fins 30 are supported in the folded state of the plastic film 32 to each other, as is indicated in Fig. 5.

The height of the cooling fins 30 can therefore be chosen to be half smaller than if they were linear and were supported directly on the adjacent water pipe 24 . In this case, the cooling fins 30 would have to be integrally formed on both foil halves 32 a and 32 b so as to be offset from one another, the engagement of the cooling fins 30 of one foil half between those of the other foil half again resulting in a reduction in the cross section of the cooling air ducts.

As shown in FIGS. 4b and 6b, there is a constructive difference in this embodiment of the plastic film 32 compared to that in FIGS. 4a and 6a in that the flat-side tube wall parts 26 , 28 have a corrugated cross section, the two wavy lines preferably being parallel to one another run. As a result, due to the increase in surface area of the flat tube, a significant increase in the cooling effect can be achieved.

As can be seen from FIG. 8, the polyamide film 32 also has a reinforcement insert in the form of a grid 48 which increases its strength and which can consist of glass or carbon fibers with a length of preferably 30 mm. Fibers made of highly tear-resistant material, such as aramid, are particularly suitable for this.

The grid 48 is oriented in the polyamide film 32 in such a way that to form the cooling fins 30, the mesh openings 50 take a diamond shape in the vertical direction of the cooling fins 30 . The oblique course of the mesh threads 52 at 45 ° in this case gives the mesh 48 great elasticity or elasticity during the thermal deformation of the polyamide film 32 .

Alternatively, the plastic film can be short or long fibers are reinforced, advantageously short fibers with a relatively large web height and long fibers, for example can be used with a relatively short web height.

The frame legs 20, 22 is in the illustrated inventive design of the fluid tubes 24 so far still significant importance, as through this the liquid pipes 24 is prevented in the vertical direction of their webs 30 seems to operate Press ballooning.

Claims (16)

1. Liquid cooler for internal combustion engines, with a frame ( 10 ) with side frame legs ( 12 , 14 ) which are connected in a corner stiff manner via an upper and a lower frame leg ( 22 ), one of the frame legs having a cooling water inlet connection ( 16 ) and the opposite one a cooling water outlet connection ( 18 ) and within the frame ( 10 ) a cooling network of a plurality of liquid tubes ( 24 ) is arranged, the ends of which are connected to the cooling water inlet or outlet connection having chamber of frame legs ( 12 , 14 ), thereby characterized in that the liquid tubes ( 24 ) in the frame ( 10 ) are adjacent to one another in a common plane, that web-like cooling fins ( 30 ) are provided on the outside of the liquid tubes ( 24 ) on the outside in the longitudinal direction of the tube at a distance from one another and that the Liquid pipes ( 24 ) with cooling fins ( 30 ) consist of at least one thermally formed plastic film, the web wall parts of the cooling fins ( 30 ) designed as double-wall webs being mutually firmly connected to one another. 2. Liquid cooler according to claim 1, characterized in that each of the liquid tubes ( 24 ) have the cross section of a flat tube. 3. Liquid cooler according to claim 2, characterized in that the web-like cooling fins ( 30 ) of the liquid tubes ( 24 ) are opposite one another on the tube flat sides. 4. Liquid cooler according to claim 2, characterized in that the web-like cooling fins ( 30 ) of the liquid tubes ( 24 ) are provided on the tube flat sides offset from one another to a gap. 5. Liquid cooler according to claim 1 or 2, characterized in that the web-like cooling fins ( 30 ) of the liquid tubes ( 24 ) are slightly curved and parallel to each other. 6. Liquid cooler according to one of the preceding claims 2 to 5, characterized in that the two flat-side tube wall parts ( 26 , 28 ) of the liquid tubes ( 24 ) are corrugated in cross section, the two wavy lines running parallel to one another. 7. Liquid cooler according to one of the preceding claims, characterized in that the liquid tubes ( 24 ) are formed by two plastic foils ( 32 a and 32 b) which are brought into register with one another and are welded to one another along the sides. 8. A liquid cooler according to claim 7, characterized in that the plastic films ( 32 a, 32 b) forming the two pipe halves of the liquid pipes ( 24 ) are brought together in one piece and by folding them, and along their two overlapping longitudinal edge parts ( 42 , 44 ) are welded together. 9. Liquid cooler according to claim 8, characterized in that the two, each having one of the tube halves parts of the plastic films ( 32 a, 32 b) along their foldable connecting piece ( 36 , 38 , 40 ) are formed in such a manner that they are brought into congruence Halves ( 32 a, 32 b) of the plastic film ( 32 ) this connecting piece ( 36 , 38 , 40 ) forms a longitudinal edge piece of the liquid tube ( 24 ) with a U-shaped cross section. 10. Liquid cooler according to one of the preceding claims 8 and 9, characterized in that the plastic film ( 32 ) consists of PA 6.6 (polyamide). 11. Liquid cooler according to claim 10, characterized in that the plastic film ( 32 ) has a thickness between 0.25 mm and 0.33 mm, preferably 0.30 mm. 12. Liquid cooler according to one of the preceding claims 7 to 11, characterized in that the plastic film ( 32 ) is fiber-reinforced. 13. Liquid cooler according to claim 12, characterized in that a grid ( 48 ) or a mat formed from highly tear-resistant threads ( 52 ) is integrated into the plastic film ( 32 ). 14. Liquid cooler according to claim 12 or 13, characterized in that the grid ( 48 ) or the mat is formed from aramid fibers. 15. Liquid cooler according to claim 13 or 14, characterized in that the grid ( 48 ) in the plastic film ( 32 ) is oriented such that its network openings ( 50 ) form a rhombus in the vertical direction of the cooling fins ( 30 ). 16. A method for producing liquid tubes for liquid coolers according to one of the preceding claims, characterized in that in the two halves ( 32 a and 32 b) of a plastic film ( 32 ) by thermal deformation in cross section to each other at least one configuration to form a respective one formed from two halves of a liquid tube ( 24 ) and in the longitudinal direction of this configuration at a distance from one another, extending transversely thereto, a plurality of cooling fins ( 30 ) forming double-walled webs and at the same time the web wall parts of which are firmly connected to one another, so that the two subsequently Film halves ( 32 a and 32 b) are brought to cover by folding the plastic film ( 32 ) in such a way that their configurations complement one another to form a liquid tube ( 24 ) and that finally the free longitudinal edge parts ( 42 , 44 ) of both film halves ( 32 a, 32 b) close together v be welded.