DE19933913C2 - Evaporator of an automotive air conditioning system - Google Patents

Abstract

The invention relates to an evaporator (2) of a motor vehicle air conditioning system with an elongate collector (4), the collector jacket (6) of which is rounded in a pressure-stable manner and is divided into a first and a second section (8, 10) in its interior in the transverse direction of the collector , which are assigned to an inlet or an outlet for the refrigerants of the evaporator, and which have transverse slots distributed over their length, the two sections (8, 10) are common, a register of at least two-flow flat tubes (zigzag fins) interconnected 20) is provided, one end (23) of which is inserted into a transverse slot in the collector jacket in such a way that one flood (22) of the flat tubes with one section and the other flood (24) of the flat tubes (20) with the other department communicated. DOLLAR A According to the invention it is provided that the first and second walls (32, 34) of the two sections (8, 10) formed by the collector jacket (6) each have the configuration of a pressure-stable rounded tube.

Description

The invention relates to an evaporator egg ner automotive air conditioning system with the features of the Oberbe handles of claim 1. A heat exchanger with these characteristics len, but more on the conditions of a cursed sigers is turned off, is known from US 5 174 373 A.

Just like the vaporizer of the invention are at the well-known heat exchanger, the flat tubes in the external heat exchange medium, mostly ambient air of the motor vehicle arranged. An op timing against the internal pressure and in the sense of saving of material and space requirements in that the Au The outer contour of the collector is circular. But there is no optimization against the internal pressure in the two themselves Longitudinal direction of the collector and extending transversely towards complementary semicircular departments.

On the other hand, duplex heat exchangers are known at which are two rows of flat tube registers with spacing in Air direction are arranged one behind the other and each by circular tubular collector with the inner heat exchange fluid be are added, the collectors of these well-known Du plex heat exchangers free of cross-division have a circular inner cross-section. At the duplex heat can exchange the two rows of  Flat tube register different due to connecting lines can be interconnected. This is also the case of use as an evaporator. At a other known duplex heat exchanger according to DE 91 11 412 U1 the two are behind each other in the ambient air of the arranged flat tube registers of different in neren heat exchange fluids fed, for. B. on the one hand by the Cooling water from an engine cooling system and, on the other hand, through cold means of a motor vehicle air conditioner, charge air or engine oil. Even with this known duplex heat exchanger, which is not used Considered use as an evaporator Collector no division into two in the transverse direction of the following departments, which are separated by a longitudinal partition are separated from each other.

The invention has for its object a Evaporator of a motor vehicle air conditioning system with only one row of flat tubes, i.e. a simplex evaporator, the given depth of the flat tubes in the air direction and if possible at a given operating pressure of the refrigerant small dimensions in terms of installation volume and wall thickness and therefore also minimal material consumption moreover a simple connection of Allows collectors and flat tubes. In particular, it should also optimally take into account the fact that at this type of evaporator the interior of the collector in Cross direction divided into two different departments is. With an even number of floods of at least two flooding evaporator are the two departments and return flow of the refrigerant, while at unge number of wheels of inflow inlet and outlet on the same ben department may be appropriate, but in association with different interiors that are in the same department are separated from one another by at least one transverse wall.

Duplex heat exchangers are sufficient from the start then when the two flat tube registers have a continuous fin ribbing  to have the requirement of the above task in particular with regard to the construction volume optimization.

The object underlying the invention will solved according to the invention by the features of claim 1.

A first feature of the invention is initially in it to see that when the evaporator is set up only in Simplex-An order of his flat tube register each of the two departments of the collector is rounded in a pressure-stable manner and thereby in Ideally, each has a circular cross-section (An Proverb 9). The effect according to the invention is accordingly also particularly clear when you look at the circular overall cross section of a collector according to US 5 174 373 A with the circular individual cross sections of a collector according to the Invention under the two conditions compares that the two circular cross sections of both departments are the same (Claim 10 of the invention) and to the same depth of the Flat tubes should be dimensioned. It then turns out that the Circular cross section of a single department in the invention about half the diameter of the circular cross section of the gan zen collector according to US 5 174 373 A. With the same inside pressure corresponds to the reduction in the diameter of the circle cross-section by a factor of two, including a reduction the required wall thickness to half the value. Already there this saves material and costs. In addition, there is a considerable saving in height, which in the vehicle interior behind a dashboard anyway is very scarce.

At present, refrigerants such as the widely used refrigerant R 134a are still used in evaporators for motor vehicle air conditioning systems, the operating pressure of which is in the range from 10 to 30 bar. There are considerations of the environmental protection natural refrigerants such. B. use CO ₂ , which are operated in evaporators with operating pressures between 40 and 80 bar. It has been shown that the evaporator according to the invention is particularly well suited for an operating mode with CO ₂ as a refrigerant, since the saving in wall thickness makes itself particularly noticeable. It is even possible to use the evaporator according to the invention for conventional refrigerants without significant additional costs so that no reconstruction is necessary in the event of a transition to CO ₂ operation.

A collector with pressure-stable rounded Abteilun conditions is in itself z. B. from DE 91 11 412 U1 (see esp. Fig. 4) or JP abstract 08086590 (see esp. Figure) be known.

According to a second feature of the invention, A slots, which expedient (see claim 11) to the Contour of the flat tubes within the permissible maximum trough satchels are adjusted out on a separate attachment forms on which the adaptation is much easier than an integral manufactured collectors or even an integral herge wall of a department can be produced. Such one Top part can for example be made of sheet metal in a simple manner formed, which is bent accordingly. In material Like sheet metal, slots can accommodate a lot of flat tubes are easier to manufacture than in pressure-resistant material Collector wall. If this sheet is then also solder coated is (see claim 12), you also get one at the same time Solder carrier for soldering the flat tubes to the collector. Such an attachment part formed from sheet metal can be used also be easily formed with collars, which the one Extend the slots inwards and / or outwards and make it possible to spread the area between the inner surface of the solder Arrange collars and the outer surface of the flat tubes. except you can do this when working out the cross slots in the collector even without affecting the result with less pre to meet the precision requirement. For example, you can cross slit with a simple side milling cutter after extrusion  or a similar integral manufacturing process to cut.

The advantages of the invention mentioned are themselves reached when the first and second walls of the Collector, which surround the two departments of the collector, within the meaning of claims 2 to 4 of separate components forms are. You could also assign a department to each Ordered wall, possibly even by the type of tube sheet and assemble the cover in several parts in the circumferential direction, while rend but according to claim 5 an integral version of the he most and / or the second wall in the circumferential direction before is moving.

For manufacturing and strength reasons, an integral formation of the first wall, the second wall and / or an integral combination of both walls is preferred, preferably as an extruded part, die-cast part or extruded part. An integral design of a first circular tube and a second circular tube in the collector design of a duplex heat exchanger is known per se from DE 91 11 412 U1, in particular FIG. 4 with description. In this known integral design, the longitudinal partition between the two departments has a circular cross-section already formed on the integral component from the outset. This idea can also be applied to the simplex evaporator according to the invention. Even more preferred is the alternative idea of claim 7, namely to see the integral component with a longitudinal slot, into which a separate component is inserted from the outside, which forms a longitudinal partition between the two departments. By means of this separate component, a tight seal of the two divisions can be achieved in a particularly advantageous manner with respect to the end face of the respectively inserted flat tube, which engages in a transverse slot which, unlike in FIG. 4 of DE 91 11 412 U1, two departments is common. If, for example, the longitudinal partition wall used as a separate component is a sheet coated with solder before, this sheet can be soldered in the soldering oven with the end face of the flat tube, in the case of an aluminum or aluminum alloy brazing.

If the transverse slots are manufactured precisely in line with the outer contour of the flat tubes within the permissible tolerances, the flat tubes can be soldered directly into the transverse slots of the component in question. However, this requires an additional application of solder, for example by plasma spraying, as is provided in the case of DE 91 11 412 U1 ( FIG. 4, reference number 75 ).

In the Simplex heat exchanger of US 5 174 373 A, from which the invention is based on the width of the transverse slot extends in each case in the collector only over part of the clear width of the circular pipe cross-section. As part of the task of the Er Instead, finding is not only the full use this inner pipe cross-section, but rather another extension of the length of the respective transverse slot and thus the length of the usable flat tube in streams direction of the Um serving as an external heat exchange fluid ambient air in the motor vehicle. It should be different from the US 5 174 373 A also also the wall thickness range of Longitudinal partition as far as possible for internal warmth chambers in the flat tube that are exposed to exchange fluid can be used can be made. Regarding the wall thickness range ser longitudinal partition gives claim 13 a solution, regarding an expansion of the cross slot to the wall thickness of the Wall of the collector itself claim 14. With the simpler Production of the cross slot by means of a disc Milling cutter according to claim 15, both requirements can be met Claim 13 and claim 14 in a particularly simple manner Take into account. It is essential that in the areas  of the cross slot, which is still in the actual wall area of the collector and / or the longitudinal partition of the front of the opposite flat tube, such a return If the transverse slot is set inwards, there is a undisturbed communication between the department concerned in the collector and the critical chambers mentioned in the flat tube can be done. The precise adaptation to the respective flat Pipes are always made using the top part with its incorporated insertion slots. It has been shown that the very narrow dimensions of the transverse slots in the jacket of the collector in connection with the attachment part used and the inserted flat tubes the requirements for Do not affect the wall thickness of the collector, because the material weakening in the wall material of the collector the addition by means of the parts used and the use lots are compensated again.

In claim 16 it is finally stated that also known circuits in the evaporator according to the invention can be provided, in particular the two Divisions in the longitudinal direction of the collector in sub-divisions can be divided.

The invention is based on schemati shear drawings on several embodiments still nä explained here. Show it:

Fig. 1 shows a cross section through a erfindungsge MAESSEN evaporator;

Fig. 2, 2a, 3 and 3a on an enlarged scale, partial cross-sections through different variants of an evaporator according to the invention in the collector area, with Fig. 3 developing the specific embodiment of Fig. 1;

Fig. 4 is a partial longitudinal section through a variant of the collector according to FIGS . 2 and 3 and

Fig. 5 and 5a respectively along the flat tubes, and processing a longitudinal section through the collector of an evaporator according to the invention in the viewing direction, in two variants, namely in dreiflutiger (Fig. 5) and vierflutiger (Fig. 5a) Verschal.

Fig. 1 shows the basic structure of a erfindungsge MAESSEN double-flow evaporator 2 of a motor vehicle climate. The entire evaporator (or parts thereof) is preferably made of aluminum or an aluminum alloy such as. B. AlMn1 manufactured and brazed from its parts, for example by means of hard solder in the form of AlSi7-12.

The evaporator 2 has a register of by flat zigzag fins 21 ( FIG. 4) with each other thermally conductively connected flat tubes 20 . In general, each flat tube 20 lying outside in the register also carries a zigzag lamella, which can be followed on the outside by an end plate, not shown, which can be part of a frame structure of the register. The heat-conducting connection is preferably carried out by brazing the zigzag fins 21 to the flat tubes 20 and, if appropriate, the respective end plate. The flat tubes 20 are usually arranged equidistantly in the register and, in the installed state in the motor vehicle air-conditioning system, are usually arranged vertically in the representation according to the drawing plane of FIG. 1. This is usually an exposure to ambient air as an external heat exchange medium in the horizontal direction in the drawing plane of Fig. 1 according to the double-line arrows in Fig. 5 and 5a. The refrigerant serving as the other heat exchange medium is passed through each individual flat tube 20 , the arrows shown in FIG. 1 indicating the two floods 22 and 24 , namely with the direction of the arrow downward in FIG. 1, the one aisle-side flood 22 and with the direction of the arrow in Fig. 1 to the top, the second output-side flood 24th Along the long dimension of the cross section of each individual flat tube 20 a plurality or plurality of channels 26 is formed in this, on which the two floods are distributed, for. B. un assignment of an equal number of channels 26 to each flood 22 or 24th

The one ends 23 of the flat tubes 20 communicate with the interior of a collector 4 , which is elongated at right angles to the flat tubes 20 (see FIGS . 4 to 5a) in its transverse direction (drawing plane of FIGS . 1 to 3a) is the collector 4 in divides two departments 8 and 10 , which are completely or at least largely separated from each other by an intermediate wall 12 .

The collector jacket 6 forms a tube sheet or contributes to its formation. For this purpose, along the collector lermantels 6 in the pitch of the register of flat tubes 20 , usually equidistant, transverse slots 18 distributed, which two departments 8 and 10 are common and in each of which a flat tube 20 of the register of flat tubes 20 with its one end 23 sealed intervenes. This end 23 of the flat tube 20 is thus, like the transverse slot 18, from two divisions 8 and 10 together. The end face of the ends 23 of the flat tubes 20 are aligned both along the individual flat tube 20 and along the header 4 .

A deflection device 28 is assigned to the other ends 25 of the flat tubes 20 , which end faces are aligned along the individual flat tube as well as along the collector, within which the first flood 22 is deflected into the second flood 24 in each individual flat tube 20 . There are many possible embodiments of such a deflection device 28 . Without restricting the generality, this is formed in FIG. 1 as a cup 30 which, with its side wall 31 , which is cranked up according to FIG. 1, tightly encloses the respective flat tube 2 on the outside. Each flat tube 2 can be assigned an individual cup 30 . It is also possible to network such bowls or to form the relevant cup-shaped deflection structure on a single integral part. Above all, the aforementioned order steering function of the two floods 22 and 24 of the respective flat tube 20th

The serving as an internal heat exchange fluid Kältemit tel is performed in the evaporator 2 with respect to the direction of flow of the ambient air in cross-countercurrent. This can be seen from FIGS. 5 and 5a, in which the direction of flow of the refrigerant is illustrated with the horizontally oriented double-walled arrows. Here, the inlet 14 of the refrigerant in the collector 4 and the outlet 16 of the refrigerant from the collector 4 are each formed on a stirnsei term wall 15 and 17 of the collector 4 , for. B. as shown, as an outer nipple of a schei ben-shaped end wall 15 and 17 , which is tightly inserted into the collector jacket 6 . In FIG. 5, the inlet 14 and the outlet 16 are assigned to the same end wall 15 , while in the embodiment according to FIG. 5 a the inlet 14 is arranged on one end wall 15 and the outlet 16 on the end wall 17 . In both cases, the inlet 14 leads into the section 10 facing the flow direction of the refrigerant and out of the section 8 facing the incoming ambient air via the outlet 16 again.

In addition, the two departments 8 and 10 are each divided by a transverse wall 9 into two sub-departments 50 and 52 or 54 and 56 , in the case of FIG. 5 the inlet 14 via an intermediate pipe connection 13 through the transverse wall 9 in the chamber 10 is extended.

In Fig. 1 the basic principle of the flow of the evaporator 2 through the refrigerant is shown. The in the drawing plane of Fig. 1 in the department 8 refrigerant is along the first flood 22 leads through the first half of the channels 26 in the respective flat tube 20 , then deflected in the deflection device 28 and countercurrent to the first flood in the second Half of the channels 26 returned to the department 6 . If this direction of flow is provided along the entire evaporator, Fig. 1 is a flow of the surrounding air to the right in the plane of the drawing assuming cross-flow as the basis. In a preferred development, however, the flow type can also be provided, for example according to FIGS. 5 and 6.

In the arrangement of FIG. 5, the refrigerant coming from inlet 14 first enters the sub-chamber 52 of the department 10 , then through the associated flat tube 20 into the sub-chamber 56 of the department 8 , from there through the assigned flat tubes 20 into the sub-chamber 50 the department 10 and finally again via the associated flat tubes 20 through the sub-chamber 54 again the department 8 to the outlet 16 . In this way, the full length of the collector 4 is used , although inlet 14 and outlet 16 are arranged on the same end face of the collector 4 .

In the embodiment according to FIG. 5 a, a corresponding flow proceeding in the direction of the collector 4 from the inlet 14 to the outlet 16 takes place first from the inlet 14 into the sub-chamber 50 , from there via the assigned or common flat tubes 20 into the sub-chamber 54 . From this via the assigned or common flat tubes 20 into the sub-chamber 52 and finally from this via the assigned or common flat tubes 20 into the sub-chamber 56 , which is connected to the outlet 16 .

FIGS. 5 and 5a is common that the distribution in the compartments 8 and 10 of the collector 4 in the manner in Ab (50 to 56) are divided to division staggered subdivisions that the refrigerant in the evaporation fer 2 in the longitudinal direction the collector 4 between the two divisions from 8 and 10 back and forth.

How, in principle, the number of channels 26 in each pair can be seen in the illustrations of FIGS. 5 and 5a also that the number of fed the respective subdivision associated flat tubes can be chosen Lich depending on the requirements different 20 well of flat tubes common to accommodation could vary.

All embodiments of the evaporator 2 according to the invention have the following type of collector 4 in common: in a further development of the concept known per se, to design the collector jacket 6 rounded in a pressure-stable manner, this concept applies to the two walls 32 and 34 of the first section 8 and the second Department 10 of the collector's jacket transferred. Accordingly, the two walls 32 and 34 are each designed to be pressure-stable rounded, in the exemplary embodiments even rounded in a circular manner.

The two embodiments of FIGS. 2 and 2a show two limit cases of this concept.

Fig. 2 shows the purest form of a borderline case, in which both walls 32 and 34 are formed on a single integral component 44 , which also forms the partition 12 between the two divisions 8 and 10 integrally. The intermediate wall 12 tapers conically in the direction of the opposite ends 23 of the flat tubes 20th The apex of this conical taper can, if necessary, be wedge-shaped pointed or more or less flattened in the manner of the narrow edge of a flat web.

Fig. 2a shows the other limit case that the two walls 32 and 34 are each formed on a separate integra len component, these two components, that is, the walls 32 and 34 , via a separate component nested as a longitudinal partition 36 , here in the form of a web made of flat material 38 , which in turn forms the intermediate wall 12 between the two departments 8 and 10 . While the outer contour of the two walls 32 and 34 can remain rounded in the first borderline case according to FIG. 2 - a wide variety of deviations from which are possible - the two flat sides of the further component, preferably the web made of flat material 38 , arrive opposite flange-like conditions flats 40 of a base-shaped outer extension 41 on the two walls 32 and 34 nested between the system. Here, with or without this base formation, the two outer sides of the walls 32 and 34 can also be provided with flange-like flats 40 , for. B. for a composition of a collector 4 from more than two walls 32 , 34, etc. In Fig. 2a, these additional outer flats 40 are shown to illustrate the alternative without forming a pedestal approach.

FIGS. 3 and 3a show a preferred form of mixing between said two limiting cases. The limit case of FIG. 2 assumes that the two walls 32 and 34 are formed by an integral component 44 . From the borderline case of FIG. 2a it is maintained that the intermediate wall 12 is formed by a further component, here again in the form of a web made of flat material 38 . This further component 48 is inserted from the outside on the side of the collector 4 facing away from the register of the flat tubes 20 in a longitudinal slot 46 between the two rounded curves of the first and second walls 32 and 34 , that is to say generally brazed.

The type of interaction of the intermediate wall 12 or a longitudinal partition 36 used separately there is also illustrated using two preferred alternatives. It should be noted that these two alternatives of interaction and the two different concepts described above when creating the partition 12 - with or without a separate longitudinal partition 36 - are fully interchangeable as needed.

The first alternative is illustrated in the embodiments of FIGS. 1 and 3 using a longitudinal partition 36 used as a separate construction part, but could also be realized accordingly with integral formation of the intermediate wall 12 on the integral component 44 according to FIG. 2, in particular in the tapered configuration. Here, the intermediate wall 12 engages in a fluidly laid channel 26 a of the respective flat tube res 20 and is nested tightly between the two channel walls. As is also shown graphically in FIGS. 1 and 3, this only has a narrower channel width than the other channels 26 of the respective flat tube 20 , only for flow separation, the end channel 26 a, without this being absolutely necessary. Due to this narrower dimensioning, however, the overall depth of the evaporator 2 is kept relatively small.

A minimal overall depth is obtained after the alternative according to FIGS . 2, 2a and 3a. In this alternative, the intermediate wall 12 , which can be formed on integral component 44 according to FIG. 2 or is formed by the separate longitudinal partition wall 36 according to FIGS . 2a and 3a, acts with the outer edge 58 of a completely normal intermediate wall 60 between flow-active channels 26 of the respective flat tube 20 closely together. Here, the flow separation occurs without any additional installation depth.

More in detail, the preferred embodiments of the exporting show approximately 3, 3a and 4 following.:
The first and second walls 32 and 34 of the collector jacket 6 are ausgebil det on the integral component 44 , which can be produced in the form shown as an extruded part. The collector jacket 6 is provided in the middle with the longitudinal slot 46 , into which the longitudinal partition wall 36 can be inserted from the outside.

The longitudinal partition 36 is for soldering to the end face 62 of the flat tubes 20 and for sealing the longitudinal slot 46 to the outside with a solder layer and is available to provide enough solder material to the outside beyond the collector jacket 6 .

In the area of the transverse slots 18 , an attachment part 62 is connected to the collector jacket 6 from the outside.

This attachment part 62 is first placed on the outside of the collector jacket 6 with the smallest possible soldering gaps. Any inward-facing collars of receiving slots 72 of the attachment part 62 are pressed into the transverse slots 46 of the collector 6 for a flat tube 20 .

The top part 64 is soldered together with further soldered connections in a continuous furnace in the so-called "one-shot" process.

AlSi7-12 is preferred as the hard solder, but not one corrosive fluoride flux used. The Hartver soldering takes place at a temperature of 600-610 ° C.

Is process for pre-fixing the attachment member 64 prior to soldering the same first pressed into a device in the collector shell 6 and then secured by folding both longitudinal ends 68 to a mounting edge 70 of Samm lermantels 6 thereto.

For better assembly and soldering of the flat tube ends 23 in the attachment part 64 , an immediate receiving slot 72 of the attachment part 64 with the collar 66 is ausgebil det, in which the end 23 of the flat tube 20 is inserted. The collar 66 is adapted both to the dimensions of the flat tube 20 and to the outer contour of the collector 4 . As a result, it follows, on the one hand, gas-tight soldering of the attachment part 64 to the collector jacket 6 and, on the other hand, the collar 66 of the attachment part 64 is connected to the ends 23 of the flat tubes 20 in a gastight manner.

Since due to the pipe division, ie the spacing of the flat tubes 20 in the longitudinal direction of the collector jacket 6 , of the usual 6-15 mm, the transverse slots 18 need to be introduced into the collector jacket 6 only in the above-mentioned cycle, the pressure resistance of the collector jacket 6 is achieved by milling the Cross slots 18 only slightly disturbed.

Together with the attachment part 64 , the collars 66 of which are pressed into the transverse slots 18 of the collector jacket 6 , the initial strength of the collector jacket 6 without transverse slots 18 is then achieved again.

In order not to close the two middle channels 26 of the flat tube 20 by the first or second wall 32 or 34 of the collector jacket 6 , the transverse slot 18 of the collector jacket 6 is set back relative to the end face 62 of the flat tube 20 . A secure seal between the first and second sections 8 and 10 of the collector jacket 6 is achieved by a longitudinal partition 56 , the thickness of which is not based on the internal overpressure of the collector jacket 6 , but rather on the differential pressure between the first and second sections 8 and 8 10 or, if need be, dimensioned according to technical manufacturing considerations. In the case of a CO ₂ evaporator 2 with a required bursting pressure of the collector jacket 6 of at least 250 bar, this means that the thickness of the first and second walls 32 and 34 must be approximately 2.5 mm each, while the solder-coated one Longitudinal partition 36 can make do with less than 0.2 mm. However, in order to achieve problem-free assembly and to provide sufficient solder material and to be able to compensate for tolerances, it should have a wall thickness of approx. 1-1.5 mm.

In the case of Fig. 3, the longitudinal partition wall 36 a of the flat tube 20 is pressed to seal with the end face 62 of the flat tube 20 in an unused to the flow channel 26.

In Fig. 3a, the longitudinal partition wall 36 seals directly against a longitudinal web of the flat tube 20 serving as an intermediate wall 60 between adjacent channels 26 , so that the blocking of channels 26 is completely avoided.

To further in the embodiment of Fig. 3a with a given depth of the flat tube 20 in the air direction as minimal as possible inside diameter of the first or second section 8 or 10 of the collector jacket 6 and thus also a minimum depth of the collector jacket 6 in the direction of air and minimum height of the To receive collector jacket 6 in the flat tube direction, the collar 66 of the receiving slot 72 in the attachment part 62 extends in the outer regions to the extent of the wall thickness of the first and second walls 32 and 34 .

In the engagement area of the collar 66 of the receiving slot 72 , the transverse slot 18 in the collector jacket 6 is set against 74 at the end face 62 of the flat tube 20 at 74, so that here too the two outer channels 26 b of the flat tube 20 are not closed by the collector jacket 6 , but are connected in terms of flow to the first or second section 8 or 10 . In the area of the transverse slots 18 of the collector jacket 6 , the internal excess pressure in the evaporator 2 is only held by the attachment part 64 . While the top part 64 is continuously soldered by the inwardly erected collar 66 on the long side of the transverse slot 18 according to FIG. 3, in the case of FIG. 3a, the top part 64 on both ends of the cross slot 18 must withstand the full operating pressure of the evaporator 2 , Due to the small width of the transverse slots 18 (2 × thickness of the attachment part 64 plus flat tube thickness) of only 3-4 mm, a wall thickness of the attachment part 64 of 1-1.5 mm is sufficient.

In order to achieve the safety aspects of components in the vehicle interior, especially with operating pressures of a CO ₂ air conditioning system of up to 80 bar and bursting pressures of up to 250 bar, the tasks and functions in the collector jacket 6 according to FIGS. 3 to 4 are divided as follows :
The extruded or seamlessly drawn collector jacket 6 serves as a frame for receiving the operating and bursting pressures. Due to the manufacturing process and the shape, it can already produce burst pressure safety without any further influences from the Nocolok soldering process and through manufacturing variation in the evaporator production.

The attachment part 64 is used to provide the required soldering material. Furthermore, the minimum tolerances of the receiving slots 72 of less than 0.2 mm required for soldering in the attachment part 64 can be produced more cheaply than in the case of the transverse slots 18 in the collector jacket 6 by stamping, embossing and rolling.

In the construction according to FIG. 3a, the top part 64 also allows the inner diameter of the first or second section 8 or 10 to be reduced further, since the collar 66 of the receiving slot 72 also engages in the outer wall thickness of the collector jacket 6 . This allows a further reduction in the construction volume and the wall thickness of the collector jacket 6 at the same burst pressure.

The recessed contour 76 of the transverse slots 18 in the collector jacket 6 , which suitably corresponds to the contour of a slot milling cutter, enables the communication of the two central channels on both sides of the longitudinal partition wall 36 in the case of FIGS . 3 and 3a and also in the case of FIG. 3a of the two outer channels 26 b with the departments 8 and 10 .

Claims (16)

1. Evaporator ( 2 ) of a motor vehicle air conditioning system
with an elongated collector ( 4 ), the collector jacket ( 6 ) is rounded and in its interior in the transverse direction of the collector is divided into a first and a second section ( 8 , 10 ), which are separated from one another with an inlet ( 14 ) and are provided with an outlet ( 16 ) for the refrigerant of the evaporator, and which has transverse slots ( 18 ) distributed over its length, the two sections ( 8 , 10 ) being common,
with a register of at least two tubes of flat tubes ( 20 ), which are thermally conductively connected to one another by zigzag fins ( 21 ), one ends ( 23 ) of which are each inserted into a transverse slot ( 18 ) in the collector jacket ( 6 ) such that the one flood ( 22 ) the flat tubes ( 20 ) communicates with one department ( 8 ) and the other flood ( 24 ) of the flat tubes ( 20 ) with the other department, and
with a deflection device (28) to the said collector (4) facing away from the other ends (25) of the flat tubes (20) adjacent waves (22, 24) communicating in pairs,
characterized by
that the first and second walls ( 32 , 34 ) of both sections ( 8 , 10 ) formed by the collector jacket ( 6 ) each have the configuration of a rounded tube,
and that in the region of the transverse slots ( 18 ) of the collector jacket ( 6 ) an externally arranged attachment part ( 64 ) is provided, which in turn has consecutive receiving slots ( 72 ) for a flat tube ( 20 ) in the longitudinal direction of the collector ( 6 ), one transverse slot ( 18 ) of the collector jacket ( 6 ) is aligned with one receiving slot ( 72 ). 2. Evaporator according to claim 1, characterized in that the first and the second wall ( 32 , 34 ) are formed by separate components. 3. Evaporator according to claim 2, characterized in that the two components in turn interposed via a part as a further construction and the two departments ( 8 , 10 ) of the collector ( 4 ) separating longitudinal partition ( 36 ) are connected to each other. 4. Evaporator according to claim 3, characterized in that the longitudinal partition ( 36 ) from a flat material ( 38 ) be, which is brazed between flange-like flats ( 40 ) on the outer surface of the two walls ( 32 , 34 ). 5. Evaporator according to one of claims 1 to 4, characterized in that the first and / or the second wall ( 32 , 34 ) is or are integrally formed in the circumferential direction. 6. Evaporator according to claim 5, characterized in that the first wall and the second wall ( 32 , 34 ) are formed on an integral component ( 44 ), which at the same time bil a longitudinal partition ( 12 ) between the two departments ( 8 , 10 ) det. 7. Evaporator according to claim 5, characterized in that the first wall ( 32 ) and the second wall ( 34 ) are formed on an integral component ( 44 ) which is provided with a longitudinal slot ( 46 ), in which a separate from the outside tes component ( 48 ) is used, which forms a longitudinal partition ( 12 ) between the two departments. 8. Evaporator according to one of claims 1 to 7, characterized in that the first wall ( 32 ) and / or the second wall ( 34 ) or alternatively the integral component ( 44 ) is or are an extruded part, a die-cast part or an extruded part , 9. Evaporator according to one of claims 1 to 8, characterized in that the first wall ( 32 ) and / or the second wall ( 34 ) has or have a circular cross section. 10. Evaporator according to one of claims 1 to 9, characterized in that the first wall ( 32 ) and the second wall ( 34 ) have the same cross sections. 11. Evaporator according to one of claims 1 to 10, characterized in that the transverse slots ( 18 ) of the collector jacket ( 6 ) and / or the receiving slots ( 72 ) of the top part ( 64 ) are shaped in accordance with the outer contour of the flat tubes ( 20 ), that with direct soldering of the flat tubes ( 20 ) in the respective transverse slot ( 18 ) or receiving slot ( 72 ) the permissible maximum painting tolerances are observed. 12. Evaporator according to one of claims 1 to 11, characterized in that the attachment part ( 64 ) is formed by a sheet pre-coated with hard solder. 13. Evaporator according to claim 11 or 12, characterized in that formed in, optionally according to claim 7 by an inserted separate component ( 12 or 34 ), at the closing area of the two walls ( 32 , 34 ) their respective transverse slot ( 18 ) opposite the respective end face ( 62 ) of the flat tube ( 20 ) inserted in the receiving slot ( 72 ) is formed after being reset. 14. Evaporator according to one of claims 11 to 13, characterized in that the receiving slots ( 72 ) with at least at least one wall ( 32 ; 34 ), preferably both, at least partially engage in the extent of the wall thickness of the wall in question, wherein in the engagement area of the respective transverse slot ( 18 ) opposite the respective end face ( 62 ) of the flat tube ( 20 ) inserted in the receiving slot is set back ( 76 ). 15. Evaporator according to claims 13 and 14, characterized in that the resets ( 76 ) of the transverse slots ( 18 ) follow the cutting contour of a side milling cutter. 16. Evaporator according to one of claims 1 to 15, characterized in that the two departments ( 8 , 10 ) of the collector ( 4 ) in the manner in from one department to another against each other ver subdivisions ( 50 , 52 , 54 , 56 ) divided are that the refrigerant in the evaporator ( 2 ) in the longitudinal direction of the collector ( 4 ) between the two departments ( 8 , 10 ) is guided back and forth.