EP0912869B1 - Flat tube heat exchanger with more than two flows and a deflecting bottom for motor vehicles, and process for manufacturing the same - Google Patents

Abstract

A flat tube heat exchanger for motor vehicles has two or more flows and a deflecting bottom for deflecting adjacent flows (12) of the flat tubes. According to the invention, the deflecting bottom is subdivided into deflecting cups (20) individually associated to each flat tube (2) and interconnected only via their connection to their corresponding flat tubes (2). Also disclosed is a process for manufacturing such a flat tube heat exchanger by drawing, straightening and cutting flat tubes into sections from a coil, mechanically pre-assembling the flat tube heat exchanger from its component parts, including the flat tubes, and welding. The deflecting cups (20) are mechanically pre-assembled together with the flat tubes, after they are cut into sections and before the flat tube heat exchanger is pre-assembled together with the flat tubes.

Description

The invention relates to more than double-flow flat tube heat exchanger, especially evaporator, for motor vehicles with a deflection floor for the deflection adjacent floods of the flat tubes with the characteristics of The preamble of claim 1 just like a method of making one Flat tube heat exchanger. Such a flat tube heat exchanger with deflection bottom is from DE 195 15 528 A1 known. With such flat tube heat exchangers one has so far either as a whole from the outset connected deflecting plates or according to the prior art, of which the Invention is based, interconnected individual deflecting plates used, which then form a whole unit again. So far, this has been provided for reasons of stability, such as usually also at the other ends of the flat tubes Cohesion through the collector common to the flat tubes takes place so that this collector and the in itself contiguous deflection floor together a frame-shaped bracket form for the whole flat tube heat exchanger structure. This applies in particular to pre-assembly before soldering, about slipping out of the zigzag slats in front of the To avoid soldering.

In general, the term collector should not only be used understood an intermediate collector or collector on the output side become, but also an input-side distributor.

The invention has for its object a more than two-flow flat tube evaporator of the type mentioned to further simplify in terms of effort and manufacturability.

This task is more than two-flow Flat tube heat exchanger with the features of the generic term of Claim 1 solved by its characteristic features.

The invention represents as with the double flow Flat tube heat exchanger according to DE-A1-195 36 117, esp. Fig. 5, a departure from the idea, the redirection each in an integrally connected deflecting floor. Instead, they are also known as in this one double-flow flat tube heat exchanger of the same type prefabricated, deep-drawn reversing buttons used.

With the more than double-flow flat tube heat exchangers, to which the invention relates must within a separation for such adjacent floods be made which are not immediately within of the respective deflection cup are deflected into one another. Within the scope of the invention - and in the preferred further development according to claim 6 - is a required in a novel manner Separator in the deflection cup as local wall formation of the deflection cup integrally manufactured, which for example when Deep drawing the deflection cup with, or approximately according to claim 6 in a further operation, can be done and it can be dispensed with makes such a separator, or more the same, to have to insert separately tightly.

The individual reversing buttons can be used in the manufacture the flat tube heat exchanger, especially after Manufacturing method of claim 10, particularly simple in the pre-assembly can be included and can be done with a relatively cheaper greater depth than deflection divisions integral deflecting floors with at least one each molded separator made at the same pitch become. In addition, their use is particularly cheap, if from the point of view of being as compact as possible Construction of the flat tube heat exchanger the relative distance the flat tubes is getting smaller and smaller. The invention relates generally prefer flat tube heat exchangers, which in turn are made of aluminum or an aluminum alloy are made. The reversing buttons are correspondingly made of aluminum or an aluminum alloy. The flat tube heat exchanger itself should preferably consist of a material that matches the material the reversing button is also compatible with soldering.

One in terms of manufacture because of its simplicity preferred first alternative is shown in claim 2, with more preferred Way the full function of the respective flat tube is maintained. However, there is also one also useful second alternative according to claim 3 in Question, namely the partition between adjacent channels of floods not communicating directly in the ground from a flow-free chamber of the flat tube to be educated. Apart from that in claims 4 and 5 specific further training courses mentioned, the Teaching of claim 3 particularly simple and advantageous also do so by inserting the divider in the deflection cup the chamber to be shut down in terms of flow under its presses in at the same time locking and thereby a seal obtained by material displacement at the end of this chamber.

The development of the invention according to claim 7 favors the assembly and the strength of the flat tube. The divider has an additional central one Stop function. Claim 8 favors with flux application reliable soldering of the deflection cup from the outside with the flat tube in the particularly critical area of Separating web.

With deep-drawn parts such as those with at least one Partition trained deflection buttons is always a problem form the edge evenly because it is in the deep-drawing process even in general arises unevenly. This requires trimming this edge. This pruning can be easiest according to the geometry of the Realize claim 9 by the pruning process in in the same direction as the deep-drawing process. Besides with this unconventional tulip technique besides cheap one at the deflection buttons according to FIG. 5 the DE-A1-195 36 117 non-existent chamfer for the Flat tube or a corresponding inlet radius as an assembly aid won.

Fig. 1 eine perspektivische Ansicht eines vierflutigen Flachrohrverdampfers, dessen Fluten durch Pfeile kenntlich gemacht sind;

Fig. 2 einen Blechzuschnitt eines Bleches vor einem Tiefziehen zu einem Umlenknapf;

Fig. 3 mit Fig. 3a einen Längsschnitt und einen Querschnitt des Anschlußbereiches eines Umlenknapfes an einem Flachrohr;

Fig. 3b eine Variante von Fig. 3;

Fig. 4 einen Querschnitt durch den Trennbereich des Umlenknapfes gemäß Fig. 3a; sowie

Fig. 5, Fig. 5a und Fig. 6 Darstellungen der Anschlußweise des Umlenknapfes, wobei die Fig. 5 und 5a je einen Schnitt im Anschlußbereich an eine Flachseite des Flachrohrs quer (Fig. 5) und längs (Fig. 5a) des Flachrohrs und Fig. 6 einen Teilschnitt im Bereich der schmalen Stirnseite des Flachrohrs längs des Umlenknapfes zeigen.

The invention is explained in more detail below with the aid of schematic drawings using several exemplary embodiments. Show it:

Figure 1 is a perspective view of a four-flow flat tube evaporator, the floods are indicated by arrows.

2 shows a sheet metal blank of a sheet metal before deep drawing to a deflection cup;

3 with FIG. 3a shows a longitudinal section and a cross section of the connection area of a deflection cup on a flat tube;

3b shows a variant of FIG. 3;

FIG. 4 shows a cross section through the separating region of the deflection cup according to FIG. 3a; such as

Fig. 5, 5a and Fig. 6 representations of the connection method of the deflection cup, wherein Figs. 5 and 5a each have a section in the connection area to a flat side of the flat tube transversely (Fig. 5) and along (Fig. 5a) of the flat tube and Fig. 6 show a partial section in the region of the narrow end face of the flat tube along the deflection cup.

The flat tube heat exchanger shown in the figures is four-flow in all the illustrated embodiments trained and as an evaporator of a refrigerant circuit designed.

That does not exclude the features shown analogously also on more than double-flow flat tube heat exchangers to transmit with a different number of floods, optionally also on those flat tube heat exchangers that do not serve as an evaporator.

The flat tube heat exchanger has the following general Construction:

A larger number, typically twenty to thirty flat tubes 2 will be at constant mutual distances and aligned end faces 4. Between the flat sides 6 of the flat tubes is one Zigzag lamella 8 sandwiched. Likewise, one zigzag lamella 8 also on the two outer surfaces 4 of the outer flat tubes arranged. Every flat tube has inner stiffening webs 10 in the flat tube Divide chambers 12 acting as continuous channels. Depending on Construction depth is a number of chambers 12 from ten to thirty typical.

The specified typical ranges of the number of Flat tubes and their chambers are only preferred and not intended to be restrictive.

In a motor vehicle air conditioning system is finished Condition the block arrangement from the flat tubes 2 and the Zigzag slats 8 by outside air in the depth direction as flows through the outer heat exchange medium.

The evaporator serves as the internal heat exchange medium a refrigerant such as especially fluorocarbon, which enters the evaporator via a feed line 14 and again via an outlet line 16 from the heat exchanger exit. The supply line comes from in the refrigerant circuit its liquefier. The output line 16 leads to the compressor of the refrigerant circuit.

In the case of an evaporator, this is done on the input side Distribution of the refrigerant from the feed line 14 to the individual flat tubes through a so-called distributor. On the output side the refrigerant is collected from the outlet pipe 16 fed. If you look at the distribution and the collection can assign separate boxes are in all embodiments both functions in one collector 18 united.

This collector 18 is then on an end face 4 the flat tubes 2 arranged while on the other end 4 of the flat tubes 2 only between the floods a flow reversal occurs, here by everyone Flat tube 2 individually assigned dowels 20, which may if necessary to a unit by not shown Connecting parts can be integrated.

In the limit case of a single-flow heat exchanger would the reversing buttons 20 the function of the connections of a Output collectors can take over if they have a common one Output line is connected.

The number of more than two floods means one flow reversal at least twice in the range of the Chambers 12 formed individual channels in each flat tube 2nd Unlike with double flow, in which the deflection 20 as in its function as connecting an output collector none would need further subdivision, but only the one-time redirection function can be guaranteed would have to be used in the event of a deflection of more than two Floods in each case at least in the case of four-flow shown partition 24, so that in this case the Quadrilateral a double simple redirection in each Deflection cup 20 takes place. With an even higher number of floods if necessary, the number of partitions 24 increase.

The collector 18 is in the illustrated embodiments in principle without restricting generality composed of a tube sheet 26 and a cover 28, where appropriate, other parts to build the Collector 18 can be provided, at least in part are given below.

The free ends facing away from the deflection buttons 20 of the flat tubes 2 engage with the interior of the collector 18th communicating tightly in the tube sheet 26, accordingly with slots and possibly internal and / or outer engagement nozzle is provided.

Since the input function and the Output function of the refrigerant are combined, the Collector 18 at least a two-chamber training, which separates an input side from the output side. For this The purpose of a chamber subdivision is at least one flat web in the form of a longitudinal web, which is connected to the supply line 14 communicating entrance area in the collector 18 of one separates through the outlet chamber 18, which communicates with the output line 16.

The evaporator also needs one if possible even supply of the refrigerant on the inlet side all flat tubes 2. In the limit, you can use each one Flat tube 2 via a so-called distributor Add refrigerant separately. Usually, however, the feed takes place to neighboring groups of flat tubes where at least some groups have a higher number of flat tubes than have one, including the number of flat tubes per group can change. Each group of flat tubes becomes one dedicated entry chamber in collector 18, which immediately communicated with the relevant group of flat tubes. The entrance chambers are in the chamber division separated from one another by transverse webs designed as flat webs.

In the illustrated four-flow evaporator except for the longitudinal web that connects to the output line 16 and exit chamber passing along collector 18 delimits another one parallel to this Longitudinal bar provided. This is the one of the own entry chambers dividing crossbars in connection to the Longitudinal cross crossed at right angles. In the extension of the Cross bars between the two longitudinal bars is between these Longitudinal webs one each to the outside own entrance chamber in the group of flat tubes 2 adjacent inner deflection chamber for deflecting the second flood divided into the third flood within collector 18.

With higher numbers of floods, by the collector 18 with deflection function increases accordingly the number of longitudinal webs and the number of inner ones Deflection chambers, which are then in the transverse direction of the collector inside each other also side by side between your own Entry chambers of the groups of flat tubes 2 as well the outlet chamber are nested.

The feed line 14 communicates with the individual Entry chambers of the groups of flat tubes each over a separate supply line running in the collector 18, which varies designed and summarized in a tube can, which together with the curved outer pipe connection Lead 14 to the block valve mentioned below 50 from the narrow end of the collector 18, there the Lid 28, can be led out, the division of the refrigerant to the own supply lines to the own entrance chambers of the groups of flat tubes 2 the same behind the block valve 50 and before the beginning of the curve of the feed line 14 can be done.

The block is usually used in the finished heat exchanger from flat tubes 2 and zigzag fins 8 laterally through each a side plate adjacent to the outer zigzag lamella 46 completed, so that the side plates 48 a outer frame for the outside air flowing into the heat exchanger block form.

The flat tubes 2, the zigzag fins 8, the tube sheet 26 and the cover 28 of the collector together with the if necessary provided chamber division as well as the side panels 46 of the heat exchanger exist, expedient just like that Lead 14 and the output line 16, made of aluminum and / or an aluminum alloy and are included the sections of the line connections adjacent to the heat exchanger to the finished evaporator, the The tube sheet 26 and the cover 28 are formed from solder-coated sheet metal could be.

Without being limited to this in practice in any case with refrigerant evaporators for 1 the supply line 14 and the output line 16, the corresponding connection piece can pass into the collector 18, to two corresponding Connection piece 48 of a thermostatically controlled block valve 50 connected. This indicates the invisible opposite side two further supply side and outlet connection on.

The individual deflection cup 20 has one in the shown Embodiments essentially flat bowl bottom 62 on, of which there is a circumferential cup wall with front Wall sections 66 and longitudinal wall sections 68 rises. The flat course of the bowl bottom 62 is only here for example to understand. The longitudinal wall section 68 rises from the bottom 62 of the bowl essentially at right angles such that he has the two flat sides 6 of the associated Grips flat tube to form a solder gap. How 3 can also be seen particularly clearly also the front wall section 66 an upright Collar 70, which is the narrow end face 4 of the flat tube also encompasses to form a solder gap, with a only solder gap around the flat tube both in the front Sections as well as in the longitudinal sections arises.

Starting from the base of the upright collar 70 this one, which has only a little more width than the flat tube 2, over a rounded or according to the graphic representation rectilinear, e.g. with a helix angle of approx. 45 °, Ramp surface 72 each in the flat bowl bottom 62 about. The two front ramp surfaces 72 lie there in the direction of flow of the deflection flow in the deflection cup foremost, e.g. three, and rearmost, e.g. two, channels 12 the flat tube opposite.

The deflection cup is made from a sheet of aluminum or an aluminum alloy, which is advantageous on the later inner surface of the surface forming the deflector Braze coated, deep drawn. For each diverter 20 2 from the still flat sheet with a Division T that is greater than the division of the arrangement of the Flat tubes 2 in the flat tube heat exchanger is a sheet cutout 20 punched out and using a stamp 2, which has the contour of a flat tube 2, deep-drawn, wherein the edge sections 66 and 68 of the sheet metal section 20 to the end and longitudinal wall sections 66 and 68 of the deflection cup 20 are formed.

In the illustrated deflection buttons 20 for the four-flow Flat tube heat exchangers form two deflection cups Deflection chambers 74, each through the intermediate wall 24 in the Deflection cup are separated from each other. The in the direction of flow the flooding through the relevant flat tube 2 first deflection chamber 74 diverts the first flood into the second flood, while the other deflection chamber 74 the third flood into the fourth flood redirects. If there is a higher level of multi-flow, then not shown, at least two partitions 24 in Deflection cup 20 provided.

In the embodiments, three types are Attachment of the intermediate wall 24 shown.

Fig. 3 describes the general teaching, the separator 24 as an integral part of the deflection 20 on this train yourself. 3a and 4 describe a kind of integral formation of the intermediate wall 24, the in the manufacture of the deflection cup from a deep-drawn Sheet metal in the sense of FIG. 2 is particularly suitable. Here, the respective longitudinal wall section 68 is in each case to a perpendicular to the cup bottom 62 or vertically extending inner bead 84 deformed. The two of the same kind Inner beads 84 touch at their apices 68 Formation of the closed partition 24 or a corresponding one Separator between the chambers 74.

Various embodiments also embody different types of connection of the respective partition 24 of the deflection cup 20 to the flat tube 2.

In the embodiment of FIG. 3, the relevant partition 24 on the end face 4 of the flat tube 2 each a single stiffening web 10a of the Flat tube 2 in a sealed connection opposite, which at the four-flow flat tube heat exchanger shown in this separates the second flood from the third flood. It can the stiffening web 10a either slightly reset from the outset by the corresponding end face 4 of the flat tube 2 before connection to the intermediate wall 24 in Preparation of the connection reworked, or you can when assembling the partition 24 to deform the Make stiffening web 10a usable. Except not one shown blunt connection of the intermediate wall 24 to the Stiffening web 10a comes in particular according to FIG. 3, a connection via a rounded, profiled end face of the intermediate web 24 in question. It is understood that all mentioned Connection types with each other in all exemplary embodiments, where a single separator 10a in the flat tube 2 with a Intermediate wall 24 cooperates in the deflection cup 20, replaceable are.

An alternative of connecting the partition 24 of a deflection cup 20 on the flat tube 2 is shown in FIG. 3b. Here is a whole channel in the connection area of the partition 12a of the flat tube 2 shut down. The partition 24 the deflection cup 20 acts tightly with an insert 86 together, which in the disused channel 12a under filling from its clear cross-section engages like a cone. The insert part 86 here has an intermediate wall 24 directly interacting head piece 87, the back the stiffening webs delimiting the closed channel 12a on both sides 10 with overlaps and under stiffening the structure of the decommissioned channel 12a at the boundaries thereof Stiffening webs 10 tightly supported.

The connection of the deflection 20 to its associated Flat tube 2 is finally at the preferred connection options 5 with 5a and 6 explained in more detail.

6 is in the front connection area at the transition from the upright collar 70 to the ramp surface 72 each have a stop base 87 for the free ends Ends of the respective flat tube 2 are formed.

Generally speaking, the respective deflection cup is spoken 20 including its partition which acts as a separator 24 with the flat tube 2 as well as the entire flat tube heat exchanger brazed.

Special difficulties then arise with feeding of the flux for brazing in the area where the Partition 24 to be soldered to the flat tube 2. This is illustrated in FIGS. 5 and 5a for the special case, that the partition 24 not shown there with a single stiffening web 10a of the flat tube is soldered shall be. When a whole channel 12a is shut down in the sense 3b the arrangement would then be corresponding.

5 and 5a, the deflection cup 20 is on the inner surface 88 of its two longitudinal wall sections 68 locally on both sides of the stiffening web 10a or analogously on both sides of a closed channel 12a-je a recessed, e.g. indented, feed channel 89 for the supply of flux for brazing with the Partition of the partition 24. Such pairs of feed troughs 89 are in the two longitudinal wall sections 68 of the peripheral cup wall 64 of the deflection cup. They open at the respective free edge of the deflection cup 20 in a funnel-shaped outer tulip provided there 90 of this edge and extend somewhat according to FIG. 5 beyond the free end 4 of the flat tube to one there free inlet cross section 92 of the feed of the flux to keep the edge areas of the intermediate wall 24 open.

5 and 6 is generally the circumferential free edge of the deflection cup forming the free end of the flat tube receiving bulge 90 to the outside bent, so that the free end face 94 this free edge runs in the direction of extension of the flat tubes 2.

Claims (10)

1. Flat-tube heat exchanger for motor vehicles, in particular evaporator, with more than two flow sections, having a deflection bottom for the deflection of adjacent flow sections of the flat tubes (2) which have inner reinforcing webs (10) dividing off chambers (12) acting as continuous ducts for the individual flow sections, there being arranged in the deflection bottom, between flow sections not communicating directly with one another in the bottom, a separating web (24) which coooperates sealingly with the end of the intermediate wall between the adjacent ducts of these flow sections not directly communicating in the bottom, characterized in that the deflection bottom is composed of deflection cups (20) which are individually assigned to each flat tube (2) and are deep-drawn from aluminium or an aluminium alloy and which are connected to one another solely via their connection to the respectively associated flat tubes (2), and in that the separating web (24) is a local wall formation (84) of the deflection cup (20).
2. Flat-tube heat exchanger according to Claim 1, characterized in that the local wall formation sealingly cooperates solely with a single reinforcing web (10a) of the respective flat tube (2).
3. Flat-tube heat exchanger according to Claim 1, characterized in that the intermediate wall between adjacent chambers (12) which guide flow sections of the respective flat tube (2) not communicating directly in the bottom is formed by a flow-stilled chamber (12a) of the flat tube (2).
4. Flat-tube heat exchanger according to Claim 3, characterized in that the wall thickness of this stilled chamber (12a) is reinforced by an inserted insert part (86).
5. Flat-tube heat exchanger according to Claim 4, characterized in that the separating web (24) bears sealingly against the insert part (86).
6. Flat-tube heat exchanger according to one of Claims 1 to 5, characterized in that the separating web (24) is formed by a two-sided local compression of the longitudinal wall portions (68) of the deflection cup (20).
7. Flat-tube heat exchanger according to one of Claims 1 to 6, characterized in that the deflection cup (20) is formed with an abutment plinth (87) on the inner face of each of its two narrow sides for the free ends of the end faces of the respective flat tube (2).
8. Flat-tube heat exchanger according to one of Claims 1 to 7, characterized in that the deflection cup (20) is formed with a feed channel (88) on the inner face of each of its two longitudinal sides (68), locally in the region of the separating web, for flux for hard-soldering.
9. Flat-tube heat exchanger according to one of Claims 1 to 8, characterized in that the peripheral free edge of the deflection cup (20) is bent round outwards, so as to form a flared portion (90) receiving the free end of the flat tube (2), and runs with its end face (94) in the direction of extent of the flat tubes.
10. Method for producing a flat-tube heat exchanger according to one of Claims 1 to 9 by the drawing-off, straightening and cutting-to-length of flat tubes from a coil, the mechanical preassembly of the flat-tube heat exchanger from its structural elements, including the flat tubes, and soldering, in particular hard-soldering, using at least one-sided solder coatings, characterized in that the deflection cups are preassembled mechanically together with the flat tubes after the cutting-to-length of the latter and before the preassembly of the flat-tube heat exchanger together with the flat tubes.

Images