Abstract:
The invention concerns an engine-mounted fan shroud for use in a vehicle that has a shroud body supported by a vehicle engine, including an outer ring made of a first material having a first stiffness, and a bodyside seal extending from and being integral with the outer ring, with the bodyside seal being made of a second material having a second stiffness that is less than the first stiffness. The bodyside seal fits into and seals around a seal opening in a body-mounted shroud that is mounted to radiator support structure.

Description:
BACKGROUND OF INVENTION  
       [0001]     The present invention relates to a vehicle having an engine-mounted fan shroud.  
         [0002]     For most automobiles and trucks driven by an internal combustion engine, a cooling fan is located adjacent to heat exchangers in an engine compartment and driven by the engine. This cooling fan ensures enough air flow to prevent overheating. The heat exchangers may be, for example, a radiator and a condenser for an air conditioning system, which are typically mounted, via support structure, to the body of the vehicle. One concern with the airflow pattern generated by the fan is that the air will just recirculate, thus reducing the cooling effectiveness of the fan. As a result, in some vehicles, fan shrouds are employed that encircle the fan close to the heat exchangers.  
         [0003]     Since there may be tolerances in the position of the heat exchangers relative to the engine, and the engine and heat exchangers may move somewhat relative to each other during vehicle operation, some fan shroud assemblies have both a body-mounted shroud and an engine-mounted shroud. The body-mounted shroud mounts to and moves with the heat exchanger support structure, which is mounted to the body, and the engine-mounted shroud mounts to and moves with the engine. To ensure the shroud assembly performs its intended function, a seal is located between the engine-mounted fan shroud and the body-mounted shroud that will allow for tolerances and maintain a seal between the two even when they move somewhat relative to each other.  
         [0004]     Prior art fan shroud assemblies that include both a body-mounted shroud and an engine-mounted fan shroud have used a sealing arrangement with a metal ring and a bellows seal attached by a worm gear clamp. Other such shroud assemblies have attached a separate seal to a shroud with rivets. Still others have molded a shroud with through-holes in it, and then placed this shroud in a second mold where a seal is molded to the shroud in such a way that the seal material will flow through the holes in the shroud to mechanically secure the seal to the shroud. But all of these require the fabricating and handling of separate components—and some also require additional assembly steps—to create an engine-mounted fan shroud assembly. Thus, all require more process and assembly time than is desirable and may require the fabrication and handling of a greater number of individual parts than is desirable.  
       SUMMARY OF INVENTION  
       [0005]     An embodiment of the present invention contemplates an engine-mounted fan shroud for use in a vehicle. The engine-mounted fan shroud has a shroud body, adapted to be supported by a vehicle engine, including an outer ring made of a first material having a first stiffness, and a bodyside seal extending from and being integral with the outer ring, with the bodyside seal being made of a second material having a second stiffness that is less than the first stiffness.  
         [0006]     An embodiment according to the present invention may also contemplate an engine fan shroud assembly for use in a vehicle that includes a body-mounted shroud and an engine-mounted shroud. The body-mounted shroud, adapted to be mounted to a support structure of a vehicle body, includes a generally cylindrical seal opening. The engine-mounted fan shroud, adapted to be supported by a vehicle engine, has a shroud body including an outer ring made of a first material having a first stiffness, and a bodyside seal extending from and being integral with the outer ring and being in sealing surface contact with the seal opening, and with the bodyside seal being made of a second material having a second stiffness that is less than the first stiffness.  
         [0007]     An advantage of an embodiment of the present invention is that the engine-mounted fan shroud is formed as an integral part, thus reducing the fabrication and assembly time, and reducing the number of different parts in the overall fan shroud assembly. Only a single mold, employing a two shot process, is required to fabricate this engine-mounted fan shroud, without any post mold processes required to affixed the components to one another.  
         [0008]     Another advantage of an embodiment of the present invention is that, while the engine-mounted fan shroud is formed as an integral part, the shroud body and stators are made from a material having the required strength and stiffness properties to maintain their shape during vehicle operation while the bodyside seal is made from a material that is flexible enough to create and maintain a sealing contact with the body-mounted shroud. Thus, the increase in efficiency of the engine driven fan is still maintained by this new integral engine-mounted fan shroud. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0009]      FIG. 1  is a perspective view of a portion of an engine compartment in a vehicle, in accordance with the present invention.  
         [0010]      FIG. 2  is a perspective view, on an enlarged scale, of the engine-mounted fan shroud shown in  FIG. 1 .  
         [0011]      FIG. 3  is a section view, on an enlarged scale, of the engine-mounted fan shroud and body-mounted shroud, taken along line  3 - 3  in  FIG. 1 .  
         [0012]      FIG. 4  is a view, on an enlarged scale, of encircled area  4  in  FIG. 3 .  
     
    
     DETAILED DESCRIPTION  
       [0013]      FIGS. 1-4  show components in an engine compartment, indicated generally at  10 , with a portion of an engine, indicated generally at  12 . A radiator (heat exchanger) support structure  14  mounts to the vehicle body (not shown). Heat exchangers (not shown), such as a radiator and condenser, mount to the radiator support structure  14 . An engine driven fan (not shown) extends from the engine  12  toward the heat exchangers. The vehicle components discussed so far can be conventional and so will not be discussed further herein.  
         [0014]     A fan shroud assembly  16  includes a body-mounted shroud  18 , which is mounted to the radiator support structure  14 , and an engine-mounted fan shroud  20 , which is mounted to the engine  12 , preferably to the engine block via three mounting brackets  22  (only two of three shown). The body-mounted shroud  18  has an upper shroud  24  that is connected to a lower shroud  26 . The upper and lower shrouds  24 ,  26  each include a semi-cylindrical fan opening flange  28 ,  30 , respectively, which together define a generally cylindrical seal opening  32 .  
         [0015]     The engine-mounted fan shroud  20  includes a shroud body  36  that has a generally cylindrical outer ring  38 , a generally cylindrical central ring  40 , and a set of stators  42  that extend between the outer ring  38  and central ring  40 . The central ring  40  defines a opening through which a portion of a fan assembly (not shown) extends. The stators  42  extend generally radially and are blade shaped, with the blades being canted in order to redirect the air flow coming from the fan toward the engine  12 . The outer ring  38  includes three mounting bosses  44 , which may include optional grommet inserts  46 , to which the mounting brackets  22  attach. If the outer ring  38  does include grommet inserts  46 , preferably the inserts  46  are molded into the engine-mounted fan shroud  20 . The outer ring  38  also includes a lip  48  to which a bodyside seal  50  is molded. The bodyside seal  50  of the engine-mounted fan shroud  20  is generally circular in shape and extends generally radially outward from the outer ring  38  of the shroud body  36 .  
         [0016]     The bodyside seal  50  needs to easily flex (deform elastically) to conform to and seal against the contours of the seal opening  32 , while the shroud body  36  needs to be strong enough to be able to retain its shape so it can support the bodyside seal  50  and for the stators  42  to be stiff enough to perform their function of redirecting air flow. Accordingly, the bodyside seal  50  is made from a relatively soft, pliable (less stiff) material—for example, a thermoplastic elastomer type of material such as Santoprene® (made by ExonMobile Chemical)—while the shroud body  36  is made from a relatively strong and hard (stiff) material—for example, nylon or a similar type of hard plastic.  
         [0017]     Despite the fact that the two different portions of the engine-mounted fan shroud  20  are made from different materials, they are formed as an integral part by a sequential, two-shot injection molding process where both portions are shot in same mold (not shown). The nylon is injected into the mold to create the shroud body  36  and then the Santoprene® is injected into the same mold to create the bodyside seal  50 —creating a single part through chemical fusion at an intersection  52  of the shroud body  36  and the bodyside seal  50 . Consequently, the bodyside seal  50  and shroud body  36  are integral. The term “integral” as used herein means a part with portions thereof chemically fused together for a permanent attachment that forms a single, monolithic piece—not two separate pieces that are later mated or secured together with adhesive, or fasteners or some other means of mechanical attachment of separate pieces.  
         [0018]     Since the engine-mounted fan shroud  20  is formed as an integral piece in a single mold, there is no post molding assembly of components needed to complete it. During vehicle assembly, the body-mounted shroud  18  is fastened to the radiator support structure  14 , and the engine-mounted fan shroud  20  is inserted into the seal opening  32 , causing the bodyside seal  50  to elastically flex and partially fold back on itself (that is, extending more in an axial direction rather than in the radial direction it extends when in its unflexed position). This flexing will cause the bodyside seal  50  to bias itself against the seal opening  32 , thus sealing between the body-mounted shroud  18  and the engine-mounted fan shroud  20 . The mounting brackets  22  are secured between the engine  12  and engine-mounted fan shroud  20  to hold it in place.  
         [0019]     During vehicle operation, the engine-mounted shroud  20 , being mounted to the engine  12 , moves with the engine  12 . The body-mounted shroud  18 , being mounted to the radiator support structure  14 , which is mounted to the body (not shown), moves with the body. As a consequence, the engine-mounted fan shroud  20  will move relative to the body-mounted shroud  18 . As they move relative to each other, the bodyside seal  50  will slide relative to the seal opening  32  in the body-mounted shroud  18 . But due to its being elastically flexed and held in the seal opening  32 , it will slide and bend while staying in contact with this opening  32 . Thus, the seal between the two parts of the fan shroud assembly  16  is maintained, which prevents the air flow driven by the fan from recirculating by flowing between the body-mounted shroud  18  and the engine-mounted fan shroud  20 .  
         [0020]     While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.