Abstract:
A heat exchanger includes a plurality of tubes extending between two tank bodies. At least one tank body includes a crown portion. At least one groove is formed in the crown portion. In order to avoid the creation of a thinner wall section in the crown portion, the inner and outer surfaces that form the groove are offset from each other.

Description:
FIELD 
       [0001]    The present disclosure relates to tank bodies for heat exchangers. More particularly, the present disclosure relates to the geometry for grooves provided in the tank body that eliminate any reduction of thickness of the tank body. 
       BACKGROUND 
       [0002]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0003]    Heat exchangers are used in automotive vehicles to heat or cool various components of the vehicle. Heat exchangers typically include a pair of fluid tanks, a plurality of tubes, a plurality of fins and a pair of support members. Each of the plurality of tubes extends between the pair of fluid tanks and each of the plurality of tubes defines one or more fluid passages that are in direct communication with a tank cavity defined by each of the fluid tanks. Each of the plurality of fins is disposed between adjacent tubes to increase the heat transfer area of the heat exchanger. The pair of support members are located on opposite sides of the stacked tubes and fins to provide support for the heat exchanger. Heat is transferred between a fluid flowing in the passages of the tubes between the fluid tanks and a fluid flowing over the tubes and fins. 
         [0004]    The tank bodies that form the fluid tanks can be made from a variety of materials including metals and plastics. The specific material depends on the strength and/or temperature requirements for the heat exchanger. Plastic tank bodies have been utilized when the requirements permit and these plastic tank bodies reduce weight and costs while still providing the necessary strength and durability. In order to increase the stiffness of the plastic tank body, grooves are added to the molded plastic tank body. When the tank body has a uniform cross-section along its length, these grooves increase the stiffness without reducing the strength of the plastic tank body. 
         [0005]    Some plastic tank bodies are designed with a crown surface which is at an angle with the longitudinal length of the plastic tank body. The crown surface is typically used to locate a fluid inlet for adding additional fluid to the heat exchanger. When a vertical groove is formed in the crown surface of the plastic tank body, the wall thickness of the plastic tank body is reduced at one side of the groove and the wall thickness is increased at the opposite side of the groove due to the intersection of the groove with the crown surface. The reduced wall thickness weakens the plastic tank body. In addition, the increased wall thickness could create molding voids due to the larger volume which needs to be filled with plastic during the molding process. 
       SUMMARY 
       [0006]    This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
         [0007]    The present disclosure provides a groove design for a plastic molded tank body that maintains the same thickness at the intersection of the groove and crown surface as the thickness of the normal wall of the tank body. This is accomplished by first keeping the tangent locations of the start of the inner and outer grooves constant to maintain the normal wall thickness and then offsetting the ends of the inner and outer grooves to provide a thicker wall at the base of the groove which increases the wall thickness at the intersection of the groove and the crown surface. 
         [0008]    Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0009]    The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
           [0010]      FIG. 1  is a front view of a heat exchanger in accordance with the present disclosure; 
           [0011]      FIG. 2  is a side view of one of the tank bodies of the heat exchanger illustrated in  FIG. 1 ; 
           [0012]      FIG. 3  is a top view of the tank body illustrated in  FIGS. 1 and 2 ; 
           [0013]      FIG. 4  is a schematic illustrating the relationship between a cross-section taken in direction A-A in  FIG. 2  and a cross-section taken in direction B-B in  FIG. 3 ; 
           [0014]      FIG. 5  is a schematic illustrating the relationship between a cross-section taken in direction C-C in  FIG. 2  and a cross-section taken in direction D-D in  FIG. 3 ; and 
           [0015]      FIG. 6  is a schematic similar to  FIG. 5  but illustrating a prior art tank body. 
       
    
    
       [0016]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0017]    Example embodiments will now be described more fully with reference to the accompanying drawings. 
         [0018]    Referring to  FIG. 1 , a heat exchanger  10  is illustrated. Heat exchanger  10  comprises an upper tank body  12 , a lower tank body  14 , a plurality of tubes  16 , a plurality of fins  18  and a pair of support members  20 . 
         [0019]    Each of the plurality of tubes  16  extend between upper tank body  12  and lower tank body  14 . Each of the plurality of tubes  16  define one or more fluid passages that carry a working fluid between a chamber defined by upper tank body  12  and a chamber defined by lower tank body  14 . Each of the plurality of fins  18  is disposed between adjacent tubes  16  and are bonded or brazed to the adjacent tubes  16 . The plurality of fins  18  increase the area of the heat exchanger surface of heat exchanger  10  in order to increase the capacity and performance of heat exchanger  10 . The pair of support members  20  are located at opposite sides of the stack of tubes  16  and fins  18  to increase the strength of the stacked components. 
         [0020]    Referring to  FIGS. 1-3 , upper tank body  12  includes a filling port  30 , a fluid inlet  32  and a plurality of grooves  34 . The plurality of grooves  34  provide additional stiffness and support for upper tank body  12 . Upper tank body  12  defines a crowned portion  38  at the center of upper tank body  12  where filling port  30  is located. The crowned portion  38  is defined by a pair of walls  40  that are angled upwards as illustrated in  FIG. 1 . On each side of crowned portion  38 , upper tank body  12  defines a straight portion  42 . Lower tank body  14  includes a fluid outlet  46  and a plurality of grooves  48 . The plurality of grooves  48  provide additional stiffness and support for lower tank body  14 . As an example, if heat exchanger  10  is a radiator for cooling an engine of a vehicle, the cooling system for the vehicle including heat exchanger  10  is filled with engine coolant through filling port  30 . As the engine operates, an engine coolant pump pumps engine coolant through the engine. The engine coolant leaves the engine and is pumped to fluid inlet  32  of upper tank body  12 . The engine coolant flows through upper tank body  12 , through the plurality of tubes  16  and into lower tank body  14 . From lower tank body  14 , the engine coolant is supplied to the pump through fluid outlet  46 . As the engine coolant flows through the plurality of tubes  16 , it exchanges heat with air blown over the plurality of tubes  16  and the plurality of fins  18 . 
         [0021]    Referring now to  FIG. 4 , a comparison of a cross-section of groove  34  taken in direction AA in  FIG. 2  and a cross-section taken in direction B-B in  FIG. 3  is illustrated. In  FIG. 4 , groove  34  is located in one of straight portions  42  of upper tank body  12 . As illustrated in  FIG. 4 , groove  34  has an outer surface starting point  50 , an outer surface ending point  52 , an inner surface starting point  54  and an inner surface ending point  56 . Inner surface starting point  54  is shifted from outer surface starting point  50  by a specified amount and inner surface ending point  56  is shifted from outer surface ending point  52  by the same specified amount in order to maintain the thickness of material through groove  34  the same as the thickness of material in non-grooved portion of upper tank body  12 . The offset is the same between sections A-A and B-B because the two surfaces where these sections were taken are parallel, both being perpendicular to groove  34 . 
         [0022]    Referring now to  FIG. 5 , a comparison of a cross-section of groove  34  taken in direction C-C in  FIG. 2  and a cross-section taken in direction D-D in  FIG. 3  is illustrated. In  FIG. 5 , groove  34  is located in crowned portion  38  of upper tank body  12 . As illustrated in  FIG. 5 , groove  34  has an outer surface starting point  60 , an outer surface ending point  62 , an inner surface starting point  64  and an inner surface ending point  66 . Inner surface starting point  64  is shifted from outer surface starting point  60  by a first specified amount and inner surface ending point  66  is shifted from outer surface ending point  62  by a second specified distance where the second specified distance is different than the first specified distance. This difference has the effect of offsetting the inner surface and outer surface of groove  34  in order to keep the thickness of material in groove  34  the same or greater than the thickness of material in non-grooved portion of crowned portion  38  of upper tank body  12  and thus avoid weakening upper tank body  12 . 
         [0023]    Inner surface starting point  64  is shifted from outer surface starting point  60  by the first specified distance and the first specified distance is determined such that the thickness A of material through the bent section after outer and inner surface starting points  60  and  64  in section C-C is maintained the same as the thickness A of material in the non-grooved portion of upper tank body  12 . As illustrated in  FIG. 5 , due to the inclined surfaces of crowned portion  38 , the thickness B of material in section D-D at the bent section after outer and inner surface starting points  60  and  64  of groove  34  is increased in crowned portion  38  as compared to thickness A in section C-C. 
         [0024]    Inner surface ending point  66  is shifted from outer surface ending point  62  by the second specified distance and the second specified distance is determined such that the thickness A of material through the bent section before outer and inner surface ending points  62  and  66  in section D-D are maintained the same as the thickness A of material in the non-grooved portion of upper tank body  12 . As illustrated in  FIG. 5 , due to the inclined surfaces of crowned portion  38 , the thickness D of material in section C-C through the bent section before outer and inner surface ending points  62  and  66  of groove  34  is increased in crowned portion  38  as compared to section D-D. This has the effect of offsetting the inner surface of groove  34  with respect to the outer surface of groove  34 . 
         [0025]      FIG. 6  illustrates the prior art designs where the inner and outer surfaces of groove  34  are not offset as in the present invention. In  FIG. 6 , section C-C has both the thickness A through the bent section before outer and inner surface starting points  60  and  64  and through the bent section before outer and inner surface ending points  62  and  66 . These thicknesses A are maintained the same as the thickness A of material in a non-grooved portion of upper tank body  12 . Due to the inclined surface of crowned portion  38 , the thickness B of material in section D-D through the bent section after surface starting points  60  and  64  of groove  34  is increased in crowned portion  38  as compared to thickness A in section C-C. Due to the inclined surface of crowned portion  38 , the thickness C of material in section D-D through the bent section before surface ending points  62  and  66  of groove  34  is decreased in crowned portion  38  as compared to thickness A in section C-C. This decreased thickness represents a weakened area of upper tank body  12 . This weakened area is eliminated by the offsetting of the inner surface with respect to the outer surface of groove  34 . 
         [0026]    The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.