Abstract:
A heat exchanger for cooling oil, including a plurality of pan-shaped heat-transfer plates stacked onto one another to define alternating channels for coolant and oil, a mounting plate soldered on one side to a side of the stacked plates and adapted to mount on its opposite side to a separate component. Openings through the heat-transfer plates and the mounting plate are provided for the passage of the oil and of the coolant, where the openings in the mounting plate have recesses therearound on the side opposite the heat-transfer plates. The recesses are adapted to receive seals therein.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
   Not applicable. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   REFERENCE TO A MICROFICHE APPENDIX 
   Not applicable. 
   TECHNICAL FIELD 
   The present invention is directed toward heat exchangers, and particularly toward a stacked plate oil cooler. 
   BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIOR ART 
   Heat exchangers such as oil coolers built from pan-shaped plates are known from, for example, EP 0 828 980 B1. In such heat exchangers, the plates have bent edges and individual plates are stacked on top of one another with their edges overlapping. The media such as oil to be cooled and coolant are distributed in the heat exchanger through tubes, with the plates defining alternating channels for the two different fluids. The entire oil cooler is often screwed on a housing (e.g., on the housing of a filter using a mounting plate), with a distributor plate integrated between the oil cooler and the mounting plate. Bores are sometimes provided in the distributor plate to distribute both fluids (the coolant and the oil). 
   Another housingless oil cooler is disclosed in DE 1 97 11 258 C2, which has a reinforcing plate and a base plate for mounting the cooler. In this case, the reinforcing plate is designed as a thickened heat-transfer plate, and the base plate and reinforcing plate are soldered to the oil cooler. The base plate also has a surrounding edge with protruding brackets for securely screwing the oil cooler onto the housing of an engine block, with the connecting pieces for oil and coolant being inserted directly in suitable borings in the housing. The oil cooler is sealed against the engine block housing using seals which sit first on the connecting pieces and are also placed in a groove in the engine block housing. Moreover, the application of a groove in the housing, including the creation of a flat sealing surface on the housing, can lead to some undesirable expenditures. 
   The present invention is directed toward improving upon the above heat exchangers, including overcoming one or more of the problems set forth above. 
   SUMMARY OF THE INVENTION 
   According to an aspect of the present invention, a heat exchanger for cooling oil is provided, including a plurality of pan-shaped heat-transfer plates stacked onto one another to define alternating channels for coolant and oil, a mounting plate soldered on one side to a side of the stacked plates and adapted to mount on its opposite side to a separate component, and openings through the heat-transfer plates and the mounting plate for the passage of the oil and of the coolant, where the openings in the mounting plate have recesses therearound on the side opposite the heat-transfer plates. The recesses are adapted to receive seals therein. 
   In one form of this aspect of the present invention, the mounting plate is formed from a single metal plate, and the recesses comprise areas on the opposite side of the metal plate from which metal has been removed. 
   In another form of this aspect of the present invention, the mounting plate is formed from two sheet metal plates secured to one another along adjacent faces. In a further form, both of the metal plates are solder coated on the one side and, in a still further form, impressions are provided in the adjacent face of one of the metal plates around the recesses to provide a solder depot. 
   In still another form of this aspect of the present invention, the recesses are stamped out from the mounting plate and, in yet another aspect, the openings are stamped out from the mounting plate. 
   In a further form of this aspect of the present invention, the recesses include first and second recess portions around two of the openings and a slit between the annular recesses. In a further form, the mounting plate is formed from two sheet metal plates secured to one another along adjacent faces with the recess being stamped out of one of the sheet metal plates, and in another form, seals are receivable in the recesses, where each of the seals comprise two annular members receivable in the first and second recess portions and a connecting portion receivable in the recess slit. 
   In yet another form of this aspect of the present invention, the mounting plate includes bores for fasteners securable to the separate component. 
   In a still further form of this aspect of the present invention, annular sealing members are received in the recesses and sealing around the openings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view generally from below an oil cooler embodying the present invention; 
       FIG. 2  shows a bottom view of the oil cooler of  FIG. 1 ; 
       FIG. 3   a  is an exploded cross sectional view taken along line  3 - 3  of  FIG. 2 ; 
       FIG. 3   b  is a non-exploded cross sectional view taken along line  3 - 3  of  FIG. 2 ; 
       FIG. 4   a  is an exploded cross sectional view taken along line  4 - 4  of  FIG. 2 ; 
       FIG. 4   b  is a non-exploded cross sectional view taken along line  4 - 4  of  FIG. 2 ; 
       FIG. 5  is a partial plan view of the base plate side of the outer plate of the mounting plate; and 
       FIG. 6  shows the mounting plate of an alternative embodiment of the present invention in which separate seals are provided at each opening. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a finished soldered oil cooler  10  according to the present invention prior to installation, for example, into a housing or on an engine block. The oil cooler  10  may be suitably mounted, for example, by screws through bores  12  in the cooler mounting plate  14 . 
   The mounting plate  14  may be advantageously formed of two plates, a base plate  14   a  and an outer plate  14   b  of different thickness, with the plates  14   a,    14   b  soldered together. (As used herein, the terms solder and soldering include braze alloy and brazing.) The plates  14   a,    14   b  may also have the same external shape such as particularly illustrated in  FIGS. 1 and 2 . The inner surface  18  of the outer plate  14   b  (which is the side facing away from, e.g., the engine block) may be coated with solder to facilitate securing of the plates  14   a,    14   b  together. 
   Openings  20 ,  22  in the base and outer plates  14   a,    14   b  allow for oil flow into and out of the oil cooler  10 , respectively (as indicated by the arrows). A second set of openings  24 ,  26  allow for coolant flow into and out of the oil cooler  10 , respectively (as also indicated by arrows). 
   In accordance with the present invention, an advantageous recess  30  in the mounting plate  14  may be defined by stamping an enlarged opening  32  in the outer plate  14   b.  It should also be appreciated, however, that it would be within the scope of the present invention to provide a single mounting plate  14 , with the recess  30  suitably produced in the plate  14 , for example, by a metal-removing process such as milling. 
   As illustrated in  FIGS. 3   a,    4   a,    5  and  6 , impressions  36  may advantageously be provided in the inner surface  18  of the outer plate  14   b  near and around the openings  32  in the outer plate  14   b.  During manufacture of the oil cooler  10 , the impressions  36  provide a solder depot for solder from the inner surface  18  of the outer plate  14   b  to prevent solder from flowing during the soldering process onto the sealing surface  38  of base plate  14   a.  The impressions  36  are illustrated in  FIG. 5  as having interruptions  39  (see, e.g.,  FIG. 5 ), but they can also be made continuous. 
   Seals  40  may advantageously be mounted in the mounting plate recess  30  in accordance with the present invention. The seals  40  may advantageously include projections  44  (see  FIG. 3   a ) formed on their outside to assist in securing the seal  40  in the recess  30  so that it cannot fall out during installation of the oil cooler  10 . Further, as best illustrated in  FIGS. 4   a - 4   b,  the openings (e.g.,  20 ) in the base plate  14   a  are smaller in cross-section than the corresponding openings in the outer plate  14   b,  so that the seal  40  may be pressed into the recess  30  without risk that it will be pressed too far (e.g., into the oil cooler  10 ). As a result, a tight bond may be readily achieved between the oil cooler  10  and the component to which it is secured (e.g., the engine block). 
   As illustrated particularly in  FIGS. 2 ,  3   a  and  3   b,  bone-shaped seals  40  may advantageously be used with the present invention. The bone-shaped seal  40  includes a pair of thick, annular beads  46  connected by a thinned middle or connecting member  48 . The previously described projections  44  are provided on the beads  46 . The recesses  30  are similarly bone-shaped for suitable securing of bone-shaped seals  40  therein.  FIG. 3   a  illustrates how such a seal  40  may be placed into the stamped-out recess  30  in the outer plate  14   b,  and  FIGS. 3   b  and  5  illustrated the seal  40  in its inserted and seated position. If a single mounting plate  14  is used, the recesses  30  may be composed of two circular recesses and a rectangular recess connecting them. 
   It should be appreciated, however, that seals of other shapes may also be advantageously used with the present invention in conjunction with different shaped plate recesses. Different shapes may, for example, be desirable based on the position of the openings  20 ,  22 ,  24 ,  26 , which themselves are determined by the shape and requirements of the engine block. 
     FIG. 4   b  illustrates the oil cooler  10  with soldered-on base plate  14   a  and outer plate  14   b  and with inserted seal  40 , including channels for the coolant and the oil defined by stacking suitable pan-shaped heat-transfer plates  50 . Arrows  54  illustrate exemplary flow paths for oil between the plates  50 , and arrow  56  illustrates an exemplary flow path for coolant between the plates  50 . 
     FIG. 5  illustrates the bone shape of the recess  30  advantageously usable with the previously described bone-shaped seal  40 . Such a recess  30  includes two circular holes  60  and a slit  62  connecting the holes  60  in the outer plate  14   b.  It will be appreciated that the shape of the seal  40  and the shape of the recess  30  may be advantageously adjusted to accommodate one another according to design requirements. 
   Bores  66  may be advantageously provided in the plate  14   b  for aeration during the soldering process. 
     FIG. 6  shows an alternative embodiment, in which the recesses  30 ′ consist of separate unconnected circular holes  60 ′, which configuration may be expedient depending on the system requirements. The recesses  30 ′ are larger than the openings (e.g., openings  20 ,  26 ) to ensured that the separate annular seals are similarly not undesirably pressed into the oil cooler. The impressions  36 ′ for possible excess solder are arranged around the circular holes  60 ′. With this embodiment, four individual seals (not shown) are used (one each at the oil inlet and outlet and the coolant inlet and outlet), where each seal may advantageously be a thick annular bead providing a secure sealing function when the oil cooler is installed (e.g., on the engine block). 
   It should be appreciated that heat exchangers incorporating the above described invention may be reliably and inexpensively manufactured and installed. For example, the recesses  30  on the mounting plate  14  enables the component to which the heat exchanger is mounted (e.g., a housing or engine block) to be manufactured without grooves or similar depressions for seals, thereby simplifying the mounting of the heat exchanger on the component. The two-part design of the combined base plate  14   a  and outer plate  14   b  has additional manufacturing-technological advantages, which lead to a reduction of the manufacturing costs for the heat exchanger, because the recesses can be stamped out. Moreover, in the embodiment with the bone-shaped seals  40 , the number of the individual parts being handled during installation is minimized and the insertion of the seal  40  is simplified. 
   Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.