Patent Application
20080156472
The invention relates to a heat exchanger, in particular an exhaust-gas heat exchanger, for exchanging heat between a first fluid, in particular an exhaust gas or charge air, and a second fluid, in particular a coolant, having: a block for separate and heat-exchanging guidance of the first and second fluids; at least one block closure element for connecting the block to at least one fluid connection. The invention also relates to an arrangement for producing a heat exchanger of said type having: a block for separate and heat-exchanging guidance of the first and second fluids; at least one block closure element for connecting the block to at least one fluid connection. The invention also relates to a method for producing a heat exchanger of said type, in particular with an arrangement of said type, having the steps: providing the block for separate and heat-exchanging guidance of the first and second fluids; providing the at least one block closure element for connecting the block to at least one fluid connection.
Heat exchangers of the type specified in the introduction, in particular exhaust-gas coolers or charge-air coolers, in particular for utility vehicle applications, are characterized by ever higher power densities. This entails ever more compact installation spaces, within which ever increasing levels of power must be transmitted. This leads to diverse requirements which should be covered by future concepts of heat exchangers.
A heat exchanger of said type is for example disclosed in US 2003/0010479 A1. Said heat exchanger is an internally-finned heat exchanger in which the block is provided with a base. Internally-finned flow ducts are, in said case for exhaust gas, inserted and joined into a base in each case at the two block ends. The flow ducts are formed in a housing which is traversed by coolant, with a housing casing being closed off by the two bases at both ends in the axial direction of the heat exchanger. In said heat exchanger, there is the problem that the flow ducts which are fixed against one another on the base cannot move towards one another during the soldering process when the solder melts, so that gaps can be generated as a result, which can cause leaks in the heat exchanger. A main disadvantage in the production of a heat exchanger of said type is therefore the lack of flexibility during the soldering process, in particular in the base region. It is generally necessary, in systems with a base, to press the tube bundle of the heat exchanger and to solder said tube bundle separately, that is to say without a housing. This has proven to be complex and disadvantageous in production.
DE 100 60 102 A1 discloses a heat exchanger of the type specified in the introduction, without a base. Here, the block of the heat exchanger is a body which is traversed by coolant and which is constructed from individual plates and whose individual flow ducts are connected by means of soldered cups into which and out of which the coolant is supplied and discharged transversely with respect to the axial direction of the heat exchanger. The intermediate spaces between the flow ducts are in this case traversed by exhaust gas, with a turbulence plate being soldered into said intermediate spaces in order to improve the heat transfer. In said concept, the main disadvantage is that the housing casing is not cooled, and therefore can become very hot in particular at high loads. This can adversely affect thermal stresses and components adjacent to the heat shield in the engine bay.
In general, and in the latter document in particular, there is therefore the additional problem of thermal stresses in a heat exchanger. In general, parts which conduct the exhaust gas or charge air heat up to a very great extent, while those parts which are in contact with the coolant are heated up to a lesser extent. As a result of different thermal expansions of adjacent components which are heated up to different extents, possibly intense stresses are generated in the material, which can in the worst case lead to failure of the heat exchanger. Such thermal stresses are increasingly expected in particular in the heat exchangers specified in the introduction, which are designed for higher power densities. A particularly critical point is the transition between the heat-exchanging block, that is to say the core part, of the heat exchanger to a fluid connection, in particular a gas inlet duct. Part of the transition region is conventionally a block closure element which connects the block to the fluid connection. In the case of so-called I-flow designs of a heat exchanger, in each case one block closure element with generally in each case one fluid connection is situated on two generally opposite sides. In the case of so-called U-flow designs of a heat exchanger, a single block closure element is provided on a single side of the block, which block closure element generally connects two fluid connections. In said at least one region of the block closure element, a comparatively well-cooled, rather filigree part, constructed for example from thin sheet metal parts, of the heat exchanger is directly adjacent to a comparatively intensely-heated fluid connection which is constructed rather from thicker-walled parts, for example a gas inlet duct. Conversely, this is also the case in the region of a fluid connection in the form of a coolant connection in the vicinity of parts of the block which are heated in comparison thereto.
It would be desirable to reduce the effects of thermal stresses and at the same time to reduce the problems within the context of a production process so as to form cohesive connections, in particular of a solder production process. In general, it is intended to obtain an improved cohesive connection, for example an improved soldered connection and/or welded connection and/or adhesive connection in a production process of a heat exchanger.
The invention proceeds from here; it is an object of the invention to specify a heat exchanger which can be produced with the involvement of a cohesive connection, in particular a soldering process, with comparatively reduced problems during the cohesive connection, in particular during the soldering process, and in which at the same time the problems of thermal stresses during use are comparatively reduced. It is also an object of the invention to specify an arrangement and a method for producing a heat exchanger which likewise allow for said problems.
With regard to the heat exchanger, the object is achieved by means of a heat exchanger of the type specified in the introduction in which it is provided according to the invention that the block closure element has a contact face arranged at the block side, with a surface normal of the contact face being aligned substantially in a radial direction in order to form a radial stop for a block edge, and in which a cohesive connection, in particular as a soldered connection, is formed in a joining region between the contact face and the block edge.
With regard to the arrangement, the object is achieved by means of the invention by means of an arrangement of the type specified in the introduction, in which, according to the invention, the block closure element has a contact face arranged at the block side, with a surface normal of the contact face being aligned substantially in a radial direction in order to form a radial stop for a block edge, and with a gap provided for the formation of a cohesive connection, in particular as a soldered connection, being formed between the contact face and the block edge.
With regard to the production method, the object is achieved by means of a production process of the type specified in the introduction in which, according to the invention, the block closure element has a contact face arranged at the block side, with a surface normal of the contact face being aligned substantially in a radial direction in order to form a radial stop for a block edge, with a gap provided for the formation of a cohesive connection, in particular as a soldered connection, being formed between the contact face and the block edge, with the block closure element being plugged onto the block. In the preferred case of a soldered connection, within the context of one refinement, the gap is filled with solder and/or the solder is arranged in the direct vicinity of the gap in a region suitable for forming a solder reservoir and a soldering process is carried out, with the block edge bearing against the contact face while the solder melts.
The invention is based on the consideration that the block closure element, be it a flange or a diffuser or some other component of said type, is generally a comparatively thick-walled component which is to be connected to a likewise comparatively thick-walled component of the block. In one particularly preferred embodiment, the latter is preferably a housing of the block. A further other possibility would also be a base of the block in which flow ducts of the block are inserted.
In addition, the invention also proceeds from the consideration that, specifically in the utility vehicle applications in the medium range, there is a considerable trend towards cohesively produced, in particular soldered, heat exchanger systems, for example in which heat-transmitting internal fins are provided in gas-conducting flow ducts. It has been shown inter alia there that the connection between the duct wall and internal fins by means of a soldering process is expedient.
The invention has additionally recognized that the component dimensions after the soldering process generally differ considerably from the dimensions before the soldering process, because after the melting, as a result of the individual components moving together, a solder layer which is present in a solid layer before the soldering is partially or almost completely displaced out of a gap for the solder between the components to be soldered. In other words, the gap for the solder is generally larger than the later joining region of the soldered connection. After the solidification of the solder, there are therefore reduced component dimensions, wherein reduced component tolerances should nevertheless generally be adhered to. The invention has recognized that, in the joining of a block closure element to a block, a process is expedient which is relatively independent of component tolerances and which can cover changing gap geometries.
According to the concept of the invention, therefore, in the block closure element, a contact face arranged at the block side is provided, with a surface normal of the contact face being aligned substantially in a radial direction in order to form a radial stop for a block edge. During the production process, the block closure element is plugged onto the block. A gap provided between the contact face and the block edge for the formation of a cohesive connection, in particular as a soldered connection, is filled with solder and/or the solder is arranged in the direct vicinity of the gap in a region suitable for forming a solder reservoir. As the soldering process is carried out, the solder melts and the block edge bears against the contact face. This leads, according to the concept of the invention, to a particularly well-formed cohesive connection as a soldered connection in the joining region between the contact face and the block edge.
In very general terms, according to the concept of the invention, an improved cohesive connection is obtained between the contact face and the block edge, for example also within the context of a welded and/or adhesive connection.
In other words, the concept of the invention provides, in essence, that as the cohesive connection process, in particular soldering process, is carried out, said process leads to an abutment of the regions to be joined, in the present case the stop face and the block edge, and it is at the same time ensured by means of the connection of the block closure element to the block that, during later operation, thermal stresses are kept comparatively low. During the cohesive connection, for example soldering process, welding and/or adhesive process, the block edge of the block thus bears against the radial contact face of the block closure element. In the case of a soldered connection, this takes place at the latest when, though preferably before, the solder regions situated in the block melt. At the same time, the solder region provided for the radial contact face also melts, so that a particularly reliable soldered connection is generated.
It is accordingly provided in one particularly advantageous refinement of the invention that the block edge is of comparatively stable design. Particularly preferably suitable for this purpose is the housing of a block. In other words, the block edge is particularly preferably part of the housing, which largely prevents thermal stresses in the joining region in later operation. Other possibilities are nevertheless not ruled out; a block edge can for example also be part of a base of a block.
Further advantages of the concept of the invention are generated within the context of advantageous refinements of the invention, which can be gathered from the subclaims.
The attainment of the concept of the invention is fundamentally possible already with a contact face which is formed as a contact face which runs at least around a part of the periphery of the block closure element. It is however particularly advantageous for the contact face to run continuously along an entire periphery of the block closure element. In this way, a particularly high level of impermeability of the heat exchanger and particularly reliable joining are obtained. It is also advantageous for a profile and/or a contour of the contact face to correspond, in order to form a form-fitting connection between the contact face and the block edge, to a profile and/or a contour of the block edge. In particular in order to obtain an improved level of stability, the contact face can additionally be part of a stepped contour which runs partially or entirely along the periphery.
The contact face is particularly advantageously part of a groove contour which runs along the periphery. In other words, a cross section which runs transversely with respect to the groove is provided with a groove base and two opposing groove limbs, with one of the groove limbs in the groove contour being formed by the contact face, preferably the inner groove limb on the block closure element. A groove limb which is situated further out on the block closure element can—like an inner groove limb—run partially or entirely along the periphery of the block closure element. For this purpose, it has proven to be particularly advantageous to form a partially encircling groove limb by means of material segments which are attached to the block closure element, for example placed on or moulded on or integrally formed with the block closure element. A row of such material segments which are arranged along the periphery with in each case interposed spaces advantageously form a groove limb which runs partially along the periphery, in particular opposite a contact face which forms the other groove limb. The latter can, in a particularly preferred embodiment, run entirely along the periphery of the block closure element.
It has proven to be particularly advantageous for the block closure element to have a groove, preferably a groove in the manner explained above, in particular a groove which is formed so as to run partially or entirely around the block closure element. Said groove, or a groove which is formed in some other way, can advantageously hold a block edge. It is possible in particular for this purpose for an end-side contour of the block edge to be held in the groove, preferably directly facing or so as to bear against a groove base of the groove contour. According to the refinement of the invention explained above, it is possible in a particularly simple manner to securely plug the block closure element onto the block edge in order to hold the block closure element there in a form-fitting manner. By means of a design of a groove as explained above, or a design similar thereto, on the block closure element, the block closure element engages around a block edge. It is advantageously possible for the contact faces to be arranged at the inside and for example the said material segments to be arranged at the outside. A U-shaped groove cross section with a limb situated at the inside of the block edge and a limb situated at the outside of the block edge has for example proven to be particularly advantageous. In addition, depending on the embodiment, other groove contours can also be realized, for example V-shaped, angular or rounded groove contours.
In particular, a soldered connection has been proven to be advantageous in which the soldered connection encompasses a joining region between the contact face and block edge of less than 0.2 mm, preferably of less than 0.1 mm. It has been found that, in conventional designs of heat exchangers, the contour or the profile of an encircling contact face should particularly advantageously be designed so as to be largely form-fitting with respect to the housing inner contour after the soldering process—the stated dimensions have surprisingly been found as being particularly advantageous in order to obtain this.
This can also mean that considerable gaps can exist between the block edge and the contact face before the soldering, and relates in particular to a main soldering direction. In the present case, a main soldering direction is to be understood to mean the direction in which the greatest dimensional shrinkage is to be expected during the soldering process of a heat exchanger, and is generally the direction in which a predominant number of solder layers is arranged one above the other. Within the context of this consideration, it was found according to one refinement of the invention that gaps in the range above 0.2 mm before the soldering can adversely affect a reliable soldering process. Accordingly, within the context of one refinement of the concept of the invention, it is assumed that a shrinkage of the dimensions of a heat exchanger block takes place only in the main soldering direction, and in the direction perpendicular to the main soldering direction, only a comparatively small shrinkage of a maximum of 0.2 mm can be ensured.
Accordingly, one refinement of the heat exchanger provides that the contact face and/or the block edge, between which a form-fitting connection as a soldered connection is formed, is arranged predominantly perpendicular or at an obtuse angle with respect to a main soldering direction.
The contact face and the block edge can advantageously additionally be fixed to one another—for example by means of a cohesive connection such as one or more weld spots and/or by means of form-fitting connections such as a crimp connection, lugs or a flanged connection—at least one point before a soldered connection. In this way, it is possible to obtain that a relative movement of a corresponding part of the block and a corresponding part of the block closure element away from one another during the soldering process is largely restricted or ideally prevented entirely. This in turn permits a reliable soldering of the corresponding parts, in particular in the region of the block edge and the contact faces.
In a further preferred refinement, the contact face and the block edge, between which a cohesive connection as a soldered connection is formed, is formed predominantly in one direction along the at least one fixed point. In other words, according to said refinement, the greater part of a joining region is formed by parts of the block and of the block closure element, in particular of the block edge and of the contact face, which are largely stationary relative to one another or are even fixed, and only a lesser part of a joining region is formed by parts which are expected to be free, that is to say not fixed with respect to the block closure element, during the soldering process.
Overall, it has proven to be particularly advantageous for the contact face to be formed on an extension which projects from the block closure element at the block side. In addition, the block edge is particularly preferably formed on a housing of the block—this being the case against the background that systems with a housing have been proven to be particularly effectively realizable within the context of the concept of the invention.
It has additionally been proven that a multi-part housing, in particular a housing with a casing and a lid, are advantageous. Here, a casing will generally form base and side parts of the housing. In one particularly preferred refinement, both the casing and also the lid can be of U-shaped design, since in this way, it is possible to obtain particularly advantageous joining of the two housing parts to one another.
Within the context of one particularly preferred refinement listed in the detailed description, it has been proven to be advantageous for flow ducts of the block to be formed in the form of joined-together plates provided with cup-like connections, which plates are provided to be traversed by the second fluid, in particular coolant. In this way, it is particularly advantageously possible to obtain that, firstly, the housing can be traversed by the first fluid, in particular exhaust gas or charge air, and secondly, cooling of the housing is provided, specifically by means of the connection of the housing to the flow ducts formed from plates.
Accordingly, one particularly preferred refinement of the invention leads to a heat exchanger in which the block closure element is provided at least for connecting the block to a fluid connection in the form of an inlet opening and/or outlet opening for the first fluid, in particular charge air or exhaust gas.
The block closure element is advantageously formed in the manner of a diffuser, in particular an inlet diffuser or outlet diffuser. The formation of a block closure element in the manner also of a flange, in particular an inlet flange or outlet flange, has also proven to be advantageous.
A heat exchanger is particularly advantageously designed in the form of an exhaust-gas heat exchanger or a charge-air heat exchanger as per the present concept of the invention.
With regard to the arrangement for producing the heat exchanger, further advantages and refinements of the invention can be gathered from the corresponding subclaims.
In the arrangement, for the reasons explained above, the gap for the formation of a cohesive connection as a soldered connection is limited in width, preferably to a width of less than 0.2 mm, preferably of less than 0.1 mm.
The gap is preferably filled with solder and/or the solder is arranged in the direct vicinity of the gap in a region suitable for forming a solder reservoir. Advantageous refinements provide that the solder reservoir is formed in a spacing region formed between the block and the block closure element. Said spacing region can be obtained by means of the block closure element not being fully plugged onto the block, or by means of a bevel on the block closure element, and is explained in more detail with regard to the detailed description of examples of a spacing region, for example in the form of a play spacing or a bevel.
In addition, advantageous refinements of the arrangement are given on the basis of the knowledge of the invention that a shrinkage of the heat exchanger takes place during the soldering process in particular in the main soldering direction. Accordingly, one refinement of the arrangement provides that the contact face and the block edge are fixed to one another at least one point before a soldered connection, in particular the contact face and the block edge, between which a cohesive connection as a soldered connection is to be formed, is formed predominantly along the at least one fixed point. In the case of a multi-part housing, in particular a housing formed from a casing and a lid, it has been proven to be advantageous for the block edge and the contact face to be fixed to one another only in the region of the casing before a soldered connection. It can additionally be advantageous for the gap to encompass a width between the contact face and block edge in the region of the lid of less than 0.1 mm.
With regard to the method, advantageous refinements can be gathered from the corresponding subclaims.
In one particularly preferred refinement of the method, the block closure element is plugged into the block, so that the contact face is arranged facing the block edge. According to said refinement, it is ensured that the block edge bears against the contact face in particular in the case of a decreasing dimension of the block with respect to the block closure element in the vertical direction. In addition, this has advantages when assembling the block closure element on the block, since the contact face constitutes a guiding aid during assembly.
In one particularly preferred refinement of the method, it is also provided that the block with the block closure element is placed into a soldering stand, in particular into a soldering stand which has a lower coefficient of thermal expansion than the block and/or the block closure element. The coefficient of thermal expansion of the soldering stand is advantageously selected to be lower than that of the block and/or of the block closure element in such a way that the contact face and the block edge are pressed against one another already before the melting of the solder. A soldering stand has for example proven to be advantageous in which the soldering stand has sufficient constituents composed of carbon-fibre-reinforced material. The concept of said refinement provides that, when the block is heated during the soldering process, the block thermally expands as a result of the temperature increase, and that, as a result of the soldering stand which is thermally stable in said range, a pressing force is exerted on the block before the solder melts.
This is a considerable advantage over methods which provide the soldering under weight loading of the block, since a weight which is provided in conventional methods first acts when the solder melts. According to the concept of this refinement, however, it is advantageous in particular that a pressure is already exerted while the solder has not yet melted. A particularly secure soldered connection is therefore permitted, within the context of the refinement of the production method, by means of a suitable selection of the soldering stand and its coefficient of thermal expansion, coordinated with the block.
The block closure element and housing and further parts of the heat exchanger can be produced in an extremely varied manner and in different combinations. For example, the block closure element can particularly advantageously be produced by means of a deep-drawing process or casting process, in particular for the case that said block closure element comprises an integral diffuser. A deep-drawing process or casting process and also a punching process are additionally particularly advantageously suitable for a flange. The contact face can, in all parts, be formed particularly effectively within the context of a milling process and/or an erosion process.
The housing or the housing parts, in particular the casing and the lid, can advantageously be provided as a deep-drawn part.
While the invention has been proven to be particularly expedient within the context of use of the heat exchanger in the form of an exhaust-gas heat exchanger, in particular as an exhaust-gas cooler, for exhaust-gas cooling in an exhaust-gas recirculation system of an internal combustion engine of a vehicle and/or as an auxiliary heater for interior space heating of a motor vehicle or else as a charge-air heat exchanger, in particular as a charge-air cooler for direct or indirect cooling of charge air in a charge-air supply system for an internal combustion engine of a motor vehicle, and is to be understood in this sense, and while the invention is described in detail below on the basis of examples which substantially realize the concept of a heat exchanger in which a block is formed without a base and flow guiding ducts in the form of joined-together plates for a coolant are provided, it should nevertheless be clear that the concept described here, as claimed, is likewise expedient within the context of other applications which fall outside the explicitly listed examples in the narrower sense and which relate to applications which fall outside said examples. For example, the proposed concept of the invention could likewise be used for the application of a heat exchanger as an oil cooler, in particular for cooling engine oil and/or transmission oil. A use as a refrigerant cooler or refrigerant condenser in a refrigerant circuit of an air-conditioning system of a motor vehicle is also suitable. Further embodiments relate also to heat exchangers in which the block is provided with a base and the connection of a block closure element takes place for example to a base, or in which the heat exchanger is provided without a housing.
Exemplary embodiments of the invention are now explained below on the basis of the drawing. Said drawing is intended to illustrate the exemplary embodiments not to scale; the drawing is in fact shown in schematized and/or slightly distorted form where appropriate for explanation. With regard to enhancements of the teaching which can be directly gathered from the drawing, reference is made to the relevant prior art.
Here, it is to be taken into consideration that various modifications and changes relating to the shape and details of an embodiment may be carried out without departing from the general idea of the invention. The features of the invention disclosed in the above description, in the drawing and in the claims can be essential both individually and also in combination for the refinement of the invention. The general idea of the invention is not restricted to the precise shape or the detail of the embodiment shown and described below, or restricted to a subject matter which would be restricted in relation to the subject matter claimed in the claims. Where dimensional ranges are specified, values which fall within the specified limits should also be disclosed as limit values and be usable and claimable in any desired manner. The drawing shows, in detail, various embodiments according to the concept of the invention, with a realization in detail of the block as per a heat exchanger in the German patent application of the applicant with the file references 05 B 135 B and 05 B 286 B having been proven to be particularly advantageous. The cited applications are hereby included in the content of disclosure of this application by way of said reference.
In detail, in the drawing:
The concept of the invention has been proven to be particularly advantageous in an embodiment in which the block 5 has a number of second flow ducts (not shown in any more detail) for guiding the coolant, which second flow ducts are formed in the manner of joined-together plates which in each case form a flow duct in an intermediate space situated in between them, with the flow ducts being connected to one another by means of cup-shaped passages and being connected to a coolant connection. In said embodiment (not shown in any more detail), an exhaust gas is received into the housing 3, whereby first flow ducts for the exhaust gas are realized, and the exhaust gas is supplied is supplied through an inlet connection, in the present case on that end side of the housing which is likewise provided for attachment 7 of the block closure element 1, and is discharged on the opposite side through an outlet connection, transversely with respect to the coolant flow. In this embodiment, a flow duct can additionally be provided with heat conducting elements in the form of internal fins attached to a flow duct inner side and/or outer fins attached to a flow duct outer side. In addition, the block 5 can also have a turbulence device, for example a turbulence plate, which ensures a suitable generation of turbulence of the exhaust gas in the direction of the coolant flow ducts. In the embodiment of the block 5 described here, the block has no base, which avoids the problems, specified in the introduction to the application, during soldering of flow ducts which are inserted into a base. The embodiment explained in more detail here therefore already corresponds to a concept, without a base, which is particularly well-aimed at a soldering process. Reference is otherwise made in this regard to the above-cited applications of the applicant.
In
As can be seen by considering
The joining region, which is shown further by way of example in
Here, in
However, a block closure element 1B as a cast part in particular also offers the possibility, by means of the formation of a bevel, of a region which narrows towards the soldering point and which is extremely suitable as a solder reservoir. Here, the solder is pulled by capillary forces into a solder gap between the contact face and the block edge 15, as explained in more detail in
It is additionally possible to obtain a solder reservoir in the way illustrated in
It is additionally possible for a solder face, that is to say a contact face 9, 9A, 9B, 9C, 9D of a block closure element 1, 1A, 1B, 1C, 1D between the contact face 9 and block edge 15, to also be generated in a punching process, as is shown for example as an encircling cut edge on a deep-drawn sheet metal diffuser in
The mechanisms for a solder reservoir explained in
A further favourable embodiment is given if the block closure element has a partially or completely encircling stepped contour, as is shown in the case of block closure elements 1, 1B and 1C in
In combination with the designs of a block closure element 1, 1A, 1B, 1C, 1D explained here, a plurality of housing variants are suitable, as are shown by way of example in
With regard to
When the temperature finally reaches the soldering temperature, the solder melts, the pre-loaded components are pressed into the melting solder layer, and very effective soldering takes place in relation to conventional soldering processes which operate with weights. For a block closure element 1, 1A, 1B, 1C, 1D according to the concept of the invention, soldering with a fixed soldering stand has considerable advantages, since here, the encircling soldering faces on the block closure element are also compressed already before the solder melts. Production methods which operate with weights or clamping springs cannot obtain said advantages in contrast to the concept of the invention, which operates on the basis of taking into consideration the thermal expansion and the high rigidity of the soldering stand. In the present case, as it melts, the solder is held particularly effectively in a narrow solder reservoir—for example as in
The housing 3IV shown in
Again, in principle, there is every possibility for a block closure element—in the present case in particular a block closure element 1E—to initially be fixed to the housing 3IV in a form-fitting manner, and then fixed to said housing 3IV cohesively.
In certain applications, it has been proven that it can nevertheless be advantageous to keep the gap spaces between the lid 3AIV and casing 3BIV as narrow as possible in order to ensure comparatively high capillary forces for the distribution of solder. In other words, an excessively large solder reservoir in the form of a cavity, for example a cavity 75 in the variant shown in view (A), can prove to be undesirable. In order to advantageously also be able to ensure a defined level of dimensional stability when assembling the lid 3AIV and casing 3BIV, it is provided in the otherwise substantially identically-designed variant of view (B) that a block closure element 1E is provided with a material thickening, which forms a spacer extension 2, in the region directly above the stepped turned-out material portion of the 90 bend 71′. The end side 73 of the lid 3AIV abuts, so as to maintain a comparatively narrow gap 77, against said spacer extension 2, which is in the present case provided with an angular contour on the upper side, of the material thickening. The spacer extension 2 which is formed by the material thickening has, at the underside, a rounded contour—matched to the rounded contour of the stepped transition to the 90° bend 71′ of the casing 3BIV—in order to also keep the gap 77 there comparatively narrow. With said combination, not only is a level of dimensional stability in the assembly of the lid 3AIV and casing 3BIV ensured on account of the dimensionally accurate placement of the spacer extension 2, but additionally also a gap 77 which is kept comparatively narrow throughout. The latter ensures comparatively high capillary forces for distributing solder.
The otherwise similarly-designed variant of view (C) also provides, as a further improvement, a rounded contour formed on the upper side of the stop 2, which rounded contour can for example be obtained within the context of an embossing process of the end side 73 of the edge of the lid 3AIV. In this way, in particular a comparatively sharp inner corner in the contact face between the spacer extension 2 and end side 73 is avoided, and again, a comparatively improved narrow guidance of the gap 77 is obtained. The variant shown in view (C) has very well-formed capillary forces when assembling the lid 3AIV, the casing 3BIV and the block closure element 1E.
In summary, specified is a heat exchanger, in particular an exhaust-gas heat exchanger or charge-air heat exchanger, for exchanging heat between a first fluid, in particular an exhaust gas or charge air, and a second fluid, in particular a coolant, which heat exchanger has: a block for separate and heat-exchanging guidance of the first and second fluids; a block closure element for connecting the block to a fluid connection. In order to eliminate as far as possible the problems which occur during a soldering process, the block closure element has a contact face arranged at the block side, with a surface normal of the contact face being aligned substantially in a radial direction in order to form a radial stop for a block edge, and a cohesive connection as a soldered connection is formed in a joining region between the contact face and the block edge. The invention specifies an arrangement and a method for producing the heat exchanger.
Particularly advantageous are designs of the block closure element with a stepped contour; within the context of the production process, a block closure element which is fixed to the housing part before the soldering process, for example by means of weld spots, and a freely movable housing part which is preferably attached with an undersize; and a soldering stand for fixing the block dimension. Also advantageous are various embodiment possibilities for a block closure element, for example in the form of a cast flange with and without a stepped contour or with and without through holes for screw connections and threads or the like; a cast diffuser with and without a stepped contour; a sheet metal punched part as an insertion flange, in particular also as a precision punched part; a multi-layer, preferably soldered element composed of a plurality of sheet metal punched parts or precision punched parts; a sheet metal deep-drawn diffuser with a punched outer contour; and all combinations of said variants, for example a sheet metal punched part which is soldered to a cast diffuser. The variants specified above are also suitable for additional machining of at least parts of the soldering faces to the housing; a milling process or an erosion process are particularly preferred candidates for this purpose. Overall, the concept of the invention permits cost-effective, flexible production of a heat exchanger.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2006 057 050.2 | Nov 2006 | DE | national |
