Patent Publication Number: US-8529216-B2

Title: Jet pump retention and seal method with living hinge

Description:
FIELD OF THE INVENTION 
     The invention relates to fuel supply units for automobile vehicles and more particularly, to a jet pump assembly of a fuel supply unit that includes a seal to reduce noise in a fuel tank and to improve performance of the jet pump assembly. 
     BACKGROUND OF THE INVENTION 
     One type of a conventional fuel pump unit for supplying fuel in a vehicle includes a fuel pump disposed within a swirl pot or fuel reservoir. The reservoir is disposed near a bottom of a fuel tank. The fuel pump pumps fuel from the reservoir through a fuel filter to an engine. A pressure regulator is coupled to the filter housing and returns excess fuel to the reservoir. The fuel pump also operates a jet pump assembly that draws fuel into the reservoir to ensure that the reservoir is replenished with fuel. A housing of the jet pump assembly is typically in plastic-to-plastic contact with the bottom of the reservoir that transmits noise when the jet pump assembly is operating to replenish the reservoir with fuel. In addition, the housing-reservoir interface defines a tortuous path for fuel so that fuel is drawn substantially directly from the fuel tank. 
     Accordingly, there is a need to provide a seal structure to decoupled the jet pump assembly from the reservoir to reduce noise of the fuel pump unit and to improve the performance of the jet pump assembly. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this objective is achieved by providing a fuel supply unit that includes a fuel reservoir for holding fuel. A fuel pump is in the reservoir for pumping fuel from the reservoir. A jet pump assembly is within the reservoir for drawing fuel from a fuel tank into the reservoir. A seal structure has a flange with a living hinge. The seal structure is operatively coupled with a housing of the jet pump assembly and disposed between the housing and a portion of the reservoir, with a portion of the flange being pivoted about the living hinge such that the portion of the flange engages an interior surface of the reservoir, providing a seal between the housing of the jet pump assembly and the interior surface of the reservoir. 
     Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood from the following detailed description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts, in which: 
         FIG. 1  is a perspective view of a fuel supply unit having a jet pump assembly provided in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view of a fuel pump of a jet pump assembly of the fuel supply unit of  FIG. 1 . 
         FIG. 3  is a partial sectional view of a seal structure shown between a housing of the jet pump assembly and the reservoir in accordance with an embodiment of the invention. 
         FIG. 4  is a partial sectional view of the seal structure of  FIG. 3 . 
         FIG. 5  is a view of the seal structure of claim  4  shown coupled with a housing of the jet pump assembly and engaged with a portion of the reservoir. 
         FIG. 6  is a partial sectional view of another embodiment of the seal structure. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT 
     With reference to  FIG. 1 , a fuel supply unit, provided in accordance with an embodiment of the invention, is shown generally indicated at  10 . The unit includes a fuel pump and reservoir assembly  12  and a filter/regulator assembly  14  that receives fuel supplied by the assembly  12  and delivers the fuel to an engine. 
     As shown in  FIGS. 2 and 3 , the assembly  12  includes a fuel pump  18  and conventional jet pump assembly  16  configured to draw fuel from a fuel tank (not shown) through an opening  20  of the reservoir  22  to replenish fuel in the reservoir  22  so as to be pumped to an engine (not shown). A valve  25  is associated with the opening  20 . 
     As shown in  FIG. 3 , in accordance with an embodiment of the invention, a seal structure  24  is provided between a housing  23  of the jet pump  16  and a portion of the reservoir  22  so as to decouple the jet pump  16  from the reservoir  22  and to provide a seal between the jet pump housing  23  and the reservoir  22 . 
     In the embodiment of  FIGS. 3-5 , the seal structure  24  is preferably an elastomer having a generally cylindrical engaging portion  26  constructed and arranged to frictionally engage an outer periphery of the generally cylindrical jet pump housing  23 . As best seen in  FIG. 4 , an annular flange  28  extends from the engaging portion  26 . The flange  28  includes surfaces defining an annular extending cut-out  30  between an end portion  32  and engaging portion  26  of the seal structure  24 . The cut-out  30  defines a living hinge  31  such that such that the free end portion  32  of the flange  28  can pivot. Although the cut-out  30  is shown in the upper surface  35  of the flange  28 , it can be provided on the under surface  37  of the flange  28  of the seal structure  24 ′ as shown in  FIG. 6 . 
     With reference to  FIGS. 3 and 5 , the reservoir  22  includes an annular wall  36  extending from the bottom  38  thereof. When assembled, the free end portion  32  of the flange  28  pivots about the living hinge  31  so as to engage the annular wall  33  or interior surface of the reservoir  22  and thus provides a seal between the reservoir and the jet pump housing  23 . It has been determined that the efficiency of the jet pump assembly  16  is improved due to sealing between the jet pump housing  23  and the reservoir  22  since fuel is drawn directly from the fuel tank. The annular wall  32  can include a portion  40  ( FIG. 5 ) that extends radially towards the engaging portion  26  so as to capture the end  32  of the seal structure  24  and thus contain the jet pump housing  23  in the reservoir  22 . 
     With reference to  FIGS. 4 and 5 , the distance B is always less than the distance A within a controlled range. This ensures that the jet pump housing  23  is press-fit into the reservoir  22  in the area of the seal structure  24 , creating a tight seal. The seal structure  24  is of a material that can be exposed to fuel, such as VITON®. The seal structure  24  is preferably coupled with the jet pump housing  23  in a friction-fit arrangement, but can be overmolded onto the housing  23 . However, since the friction engagement or overmolding require an additional process, the seal structure  24  can be molded as an integral part of the housing  23  in a single molding process. For example, at the time of molding the housing  23 , preferably out of POM material, the seal structure  24  can be defined in the mold and molded from the POM material as well. 
     Thus, the seal structure  24  mechanically decouples the jet pump  16  from the bottom of the reservoir  22  to aid in noise reduction when the jet pump operates and provides a seal between the bottom of the reservoir  22  and the jet pump housing, allowing suction of fuel directly from the fuel tank. The seal structure  24  also allows for tolerance stack variations. 
     The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the spirit of the following claims.