Abstract:
A stacked-plate cooler may include a plurality of heat exchanger plates arranged one on top of the other to define a stack. A base plate may be arranged on one end of the stack. The base plate may include a planar plate and a frame plate arranged over the planar plate. The frame plate may define a bead-shaped inner edge. The bead-shaped inner edge of the frame plate may be at least linearly connected to at least one of the plurality of heat exchanger plates.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to German Patent Application No. 10 2014 212 942.7, filed Jul. 3, 2014, the contents of which are hereby incorporated by reference in their entirety. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to a stacked-plate cooler having a multiplicity of heat exchanger plates, which are arranged one on top of the other to form a stack, and having a base plate arranged on the end of the stack. The invention also relates to a base plate for a stacked-plate cooler of said type, and to a motor vehicle having a stacked-plate cooler of said type. 
       BACKGROUND 
       [0003]    Stacked-plate coolers, in particular stacked-plate oil coolers, are composed of a base plate, possibly a reinforcement plate, and the individual heat-exchanging heat exchanger plates stacked one inside the other, with or without turbulence inserts. Furthermore, a cover plate and corresponding ports, in particular oil and coolant ports, are provided. A critical location with regard to the strength of the stacked-plate cooler to withstand fluctuating pressure is the connection of the block or the reinforcement plate to the base plate. The fluctuating pressure loading and the screw connection at the edge of the base plate results in so-called “breathing” or “deformation” of the base plate, which can lead to stresses in the connection of the block or of the reinforcement plate to the base plate. The stresses in said region can be reduced by way of stiff/flexurally rigid base plates, which is however possible only through the use of a relatively large amount of material, that is to say thick metal sheets, or materials with high strength and thus expensive materials. 
         [0004]    DE 10 2010 001 828 A1 has disclosed a generic stacked-plate cooler with a stack of heat exchanger plates borne by a first base plate, wherein, in addition to a first, planar base plate, there is also provided a second base plate with a depression surrounded by a frame-like support edge supported on the first, and the stack protrudes into the depression as far as the load-bearing frame-side abutment. In this way, it is sought, while realizing a saving of material, to realize a reduced structural height while maintaining the same strength or even obtaining an increased strength. 
         [0005]    DE 010 2009 030 095 A1 has disclosed a further generic stacked-plate cooler, in particular a stacked-plate oil cooler, which has a multiplicity of heat exchanger plates arranged one on top of the other to form the stack, and a base plate arranged on one end of the stack. In this case, the base plate has an upturned edge pointing in the direction of the stack, which edge, at least in sections, follows an outline of the stack. In this way, it is sought to produce a dimensionally rigid and at the same time inexpensive base plate. 
         [0006]    As mentioned in the introduction, in the case of the stacked-plate coolers known from the prior art, the desired high strength in the region of the base plate can be realized only by way of expensive and thick materials, which materials not only have a high weight but also necessitate relatively high energy usage for the brazing process. 
       SUMMARY 
       [0007]    The present invention is therefore concerned with the problem of specifying, for a stacked-plate cooler of the generic type, an improved embodiment which is in particular more lightweight and less expensive. 
         [0008]    Said problem is solved according to the invention by way of the subject matter of the independent claims. The dependent claims relate to advantageous embodiments. 
         [0009]    The present invention is based on the general concept, in the case of a stacked-plate cooler such as is known per se, in particular in the case of a stacked-plate oil cooler, with a multiplicity of heat exchanger plates, which are arranged one above the other to form a stack, and having a base plate arranged on the end of the stack, of constructing said base plate in two parts, specifically from a planar plate and, arranged over the latter, a frame plate with a bead-like inner edge, wherein said inner edge, in the assembled stacked-plate cooler, is at least linearly connected in cohesive fashion to one of the heat exchanger plates, and supports said one of the heat exchanger plates at the edge. By means of the bead-like inner edge, it is possible to realize considerable stiffening of the frame plate and furthermore of the planar plate or of the base plate, without the hitherto required high and thus also expensive and heavy outlay in terms of material. The frame plate with the bead-like inner edge can in this case be produced relatively inexpensively as a sheet-metal punched part, wherein the turning-up or folding-up of the bead-like edge can be realized in a simple manner in terms of manufacturing, for example by way of a corresponding upsetting process or bending process. The bead-like inner edge stiffens the frame plate and, by way of the latter, also the entire base plate, in such a way that it is possible to dispense with the material thickness hitherto required for this purpose. In this way, it is possible for not only the base plate but, by way of the latter, also the entire stacked-plate cooler, to be of considerably more lightweight construction, which is of great advantage in particular with regard to use in modern motor vehicles with regard to fuel consumption. Also, during brazing of the frame plate to the plate of the base plate, less energy is required owing to the reduced material thickness, whereby the production of the base plate can be made more environmentally compatible. 
         [0010]    The plate expediently has a thickness d 1  of approximately 1 to 6 mm. The plate of the base plate has hitherto been produced from solid material, with a thickness of approximately 4 to 12 mm, resulting, in the worst case, in a weight 12 times that of the plate according to the invention, together with the associated high material costs and high weight. 
         [0011]    In a further advantageous embodiment of the solution according to the invention, the frame plate has a thickness d 2  of approximately 1 to 4 mm. By comparison with previous reinforcement plates, the frame plate according to the invention is also of considerably thinner form, as the required stiffness is, according to the invention, realized no longer by way of the material thickness but by way of the inner edge running in bead-like form. In this case, the inner edge may be of fully encircling form, or may run around only a part of the subsequent heat exchanger plate. 
         [0012]    It is expediently the case that a flank angle a of the bead-like inner edge corresponds to a rim angle β of a rim of the heat exchanger plate, such that the bead-like inner edge can be connected areally to the heat exchanger plate in the assembled stacked-plate cooler. In this specific case, it is thus possible to realize an areal brazed connection between the bead-like inner edge and the rim, that is to say the turned-up edge of the heat exchanger plate, whereby a particularly well-sealed connection can be realized. By means of the areal brazed connection, it is also possible for the occurring pressure pulsations to be better absorbed. 
         [0013]    It is expediently the case that, for a height h of that flank of the bead-like inner edge which faces toward the heat exchanger plate, the following condition applies: b&lt;h&lt;a, where a represents the maximum height of the bead-like inner edge and b describes the spacing of the bead-like inner edge from the plate. The spacing b in this case lies between the maximum height a of the bead-like inner edge and zero. Here, the above-described condition alone gives an indication of the variety of possible embodiments of the stacked-plate cooler according to the invention, such that it is possible to realize all embodiments ranging from a brazed connection of the flank over the entire height to only a linear brazed connection. 
         [0014]    In a further advantageous embodiment of the solution according to the invention, the plate and/or the frame plate are in the form of sheet-metal punched parts. This makes it possible for the base plate to be produced in an inexpensive manner which is simple in terms of manufacture but nevertheless with high precision, wherein, for the connection of the plate to the frame plate, at least one of the two plates is braze-plated or has a braze foil correspondingly applied thereto. In this way, brazing is possible in a relatively simple manner in a corresponding brazing furnace. 
         [0015]    Further important features and advantages of the invention will emerge from the subclaims, from the drawings and from the associated description of the figures on the basis of the drawings. 
         [0016]    It is self-evident that the features mentioned above and the features yet to be discussed below may be used not only in the respectively specified combination but also in other combinations or individually without departing from the scope of the present invention. 
         [0017]    Preferred exemplary embodiments of the invention are illustrated in the drawings and will be discussed in more detail in the following description, wherein identical reference signs relate to identical or similar or functionally identical components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    In the figures, in each case schematically: 
           [0019]      FIG. 1  shows a base plate designed according to the invention, in an exploded illustration, 
           [0020]      FIG. 2  shows a sectional illustration through a stacked-plate cooler according to the invention, 
           [0021]      FIG. 3  is a detail illustration of the detail A from  FIG. 2  in a modified embodiment, 
           [0022]      FIG. 4  is the detail illustration A from  FIG. 2 , 
           [0023]      FIG. 5  is an illustration as in  FIG. 3 , but in the case of a further modified embodiment of the inner edge. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Correspondingly to  FIGS. 2 to 5 , a stacked-plate cooler  1  according to the invention, for example a stacked-plate oil cooler for a motor vehicle, has a multiplicity of heat exchanger plates  2 , which are arranged one on top of the other to form a stack, and a base plate  3  arranged on the end of the stack. In this case, the illustration does not show a cover plate which is arranged on top of the stack and which has corresponding ports for coolant and/or oil. According to the invention, the base plate  3  is in this case of two-part construction, being composed specifically of a planar plate  4  and, arranged over the latter, a frame plate  5  with a bead-like inner edge  6 . By means of the turned-up and bead-like inner edge  6 , it is possible to realize considerably improved stiffening of the frame plate  5  and furthermore of the base plate  3  as a whole, such that the base plate  3  according to the invention can be considerably thinner than base plates known from the prior art, that is to say can be formed with considerably less material and thus also so as to be of considerably lower weight. 
         [0025]    In this case, according to the invention, the plate  4  has a thickness d 1  of only 1 to 6 mm, which is a considerable reduction in relation to plates known from the prior art, which have a thickness of up to 12 mm. According to the invention, the frame plate  5  has a thickness d 2  between approximately 1 and 4 mm and is thus, according to the invention, likewise considerably thinner, and thus also considerably lighter, than similar reinforcement plates known from the prior art. Altogether, it is thus possible in the case of the stacked-plate cooler  1  according to the invention to use a base plate  3  which is reduced in thickness and weight but which exhibits similar or even better stiffness than solid-material base plates hitherto known from the prior art. Owing to the reduced usage of material, the amount of energy that must be expended during a process of brazing the frame plate  5  to the plate  4  of the base plate  3  is considerably reduced, which has a positive effect on an ecological balance. 
         [0026]    In general, it is possible for the frame plate  5  to be formed as an inexpensive sheet-metal punched part, and for the bead-like inner edge  6  to either simply be stamped or punched, such as is illustrated for example in  FIG. 3 , or to be correspondingly deformed, as illustrated in  FIGS. 2 and 4  and  5 . In order to be brazed to one another, the frame plate  5  and/or the plate  4  are provided with a braze plating or a corresponding braze foil. 
         [0027]    Considering  FIG. 3 , it can be seen that the bead-like inner edge  6  is connected linearly to a rim  7 , that is to say to an edge of the heat exchanger plate  2 , and is thus also only linearly brazed to said rim. By contrast, in the embodiments of the bead-like inner edge  6  illustrated in  FIGS. 2 and 4 , a flank angle a of the bead-like inner edge  6  is selected so as to correspond to a rim angle β of the heat exchanger plate  2 , that is to say to a rim  7  of the heat exchanger plate  2 , and thus the bead-like inner edge  6 , in the assembled stacked-plate cooler  1 , is connected areally to the rim  7  of the heat exchanger plate  2 , in particular by brazing. In this way, it is possible under some circumstances for the pressure pulsations that occur in said region to be absorbed, or introduced into the base plate  3 , in a particularly effective manner. 
         [0028]    By contrast, considering  FIG. 5 , it can be seen that, for a height h of that flank of the bead-like inner edge  6  which faces toward the heat exchanger plate  2 , the following condition applies: 
         [0000]      b&lt;h&lt;a, where 0&lt;b&lt;a, 
         [0000]    where a represents the maximum height of the bead-like inner edge  6  and b denotes the spacing between the bead-like inner edge  6  and the plate  4 , wherein b lies between 0 and a. In general, in this case, the bead-like inner edge  6  is formed so as to fully encircle the heat exchanger plates  2 , wherein it is self-evidently also conceivable for said bead-like inner edge to be arranged only over a part of the inner edge of the plate  4 . In general, by means of the bead-like inner edge  6  according to the invention, the critical location for fluctuating pressure loading of the raised connection of the heat exchanger plate  2  to the base plate  3  can be relocated to a stiffer and stronger location, which leads overall to an increase in strength. A further function of the bead-like inner edge  6  is that of increasing the wall thickness in the region of the rim  7  of the lowermost heat exchanger plate  2 , whereby the reinforcement plate that has hitherto been required in said region can be omitted, because said function is now performed by the frame plate  5  or by the bead-like inner edge  6  thereof. 
         [0029]    With the base plate  3  according to the invention and in particular also with the stacked-plate cooler  1  according to the invention, it is furthermore possible for the required structural height of the stacked-plate cooler  1  to be reduced while maintaining the same performance/pressure loss ratio. Owing to the omission of the hitherto required reinforcement plates, the production tooling hitherto required for this purpose is also no longer needed, whereby the overall manufacturing outlay can be reduced. Furthermore, it is possible to realize a reduction in weight and a reduction and material outlay, whereby the base plate  3  according to the invention and thus also the stacked-plate cooler  1  according to the invention can be produced in an inexpensive and environmentally compatible manner.