Abstract:
A wear resistant fuel pump for a vehicle includes a pump section having a flow channel and a rotatable impeller cooperating with said flow channel to pump fuel therethrough. The fuel pump also includes a motor section disposed adjacent the pump section and having a motor to rotate the impeller. The fuel pump further includes an outlet section disposed adjacent the motor section to allow pumped fuel to exit the fuel pump. The pump section includes a plurality of plates disposed axially adjacent to and cooperating with the impeller. At least one of the plates includes a wear insert that improves abrasion wear characteristics therebetween.

Description:
TECHNICAL FIELD 
     The present invention relates generally to fuel pumps for vehicles and, more particularly, to a wear resistant fuel pump for a vehicle. 
     BACKGROUND OF THE INVENTION 
     It is known to provide a fuel tank in a vehicle to hold fuel to be used by an engine of the vehicle. It is also known to provide a fuel pump to pump fuel from the fuel tank to the engine. One type of fuel pump is known as a high-pressure turbine fuel pump. The high-pressure turbine fuel pump typically includes a plastic impeller rotatable between solid materials such as anodized aluminum plates. The anodized aluminum material of the plates provides for a high wear resistant and high strength surface. However, a die casting process used to form the plates limits the geometric complexity and surface smoothness of a flow channel and port areas of the plates. Otherwise, the plates are machined to obtain complex shapes, which is relatively expensive. In addition, secondary operations are required for surface anodization and insertion of a journal bearing. 
     Improved geometry and surface smoothness can be obtained using injection or compression molded plastic plates. However, plastic plates have traditionally been limited in their applications due to poor abrasion wear resistance. Otherwise, the sealing surfaces of the plates wear, resulting in a reduction of fluid flow output. 
     Therefore, it is desirable to provide fuel pump for a vehicle having insert molded plates that improves the abrasive wear characteristics of plates. It is also desirable to provide a wear resistant fuel pump for a vehicle having insert molded plates with complex shapes. It is further desirable to provide insert molded plates in a fuel pump that improve wear resistance, strength, and surface smoothness. 
     SUMMARY OF THE INVENTION 
     It is, therefore, one object of the present invention to provide a wear resistant fuel pump for a vehicle. 
     It is another object of the present invention to provide a fuel pump for a vehicle having plates that are insert molded to improve the abrasive wear characteristics of the plates. 
     To achieve the foregoing objects, the present invention is a wear resistant fuel pump for a vehicle including a pump section having a flow channel and a rotatable impeller cooperating with said flow channel to pump fuel therethrough. The wear resistant fuel pump also includes a motor section disposed adjacent the pump section and having a motor to rotate the impeller. The wear resistant fuel pump further includes an outlet section disposed adjacent the motor section to allow pumped fuel to exit the fuel pump. The pump section includes a plurality of plates disposed axially adjacent to and cooperating with the impeller. At least one of the plates includes a wear insert that improves abrasion wear characteristics therebetween. 
     One advantage of the present invention is that a wear resistant fuel pump is provided for a vehicle. Another advantage of the present invention is that the wear resistant fuel pump has insert molded plates that improve the abrasive wear characteristics of the fuel pump. Yet another advantage of the present invention is that the wear resistant fuel pump reduces cost by eliminating or reducing machining and secondary operations. Still another advantage of the present invention is that the wear resistant fuel pump improves wear resistance and strength and allows complex shapes to be made at a relatively low cost. A further advantage of the present invention is that the wear resistant fuel pump has insert molded plates made into relatively simple shapes, thereby allowing more materials to be available for the wear resistant portion of the plate. 
     Other objects, features, and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary elevational view of a wear resistant fuel pump, according to the present invention. 
     FIG. 2 is a perspective view of an outlet plate of the wear resistant fuel pump of FIG.  1 . 
     FIG. 3 is a perspective view of a portion of the outlet plate of FIG.  2 . 
     FIG. 4 is an enlarged plan view of the portion of FIG.  3 . 
     FIG. 5 is a sectional view taken along line  5 - 4  of FIG.  4 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings and in particular FIG. 1, one embodiment of a wear resistant fuel pump  12 , according to the present invention, is shown for a vehicle (not shown). The wear resistant fuel pump  12  includes a pump section  14  at one axial end, a motor section  16  adjacent the pump section  14  and an outlet section  18  adjacent the motor section  16  at the other axial end. As known in the art, fuel enters the pump section  14 , which is rotated by the motor section  16 , and is pumped past the motor section  16  to the outlet section  18 . The outlet section  18  has an outlet member  20  extending axially with a passageway  22  extending axially therethrough. The outlet member  20  also has a plurality of projections or barbs  24  extending radially outwardly for attachment to a conduit (not shown). The outlet member  20  also includes a check valve  26  disposed in the passageway  22 . It should be appreciated that the fuel flowing to the outlet section  18  flows into the outlet member  20  and through the passageway  22  and check valve  26  when open to the conduit. It should also be appreciated that, except for the pump section  14 , the fuel pump  12  is conventional and known in the art. 
     Referring to FIGS. 1 through 6, the pump section  14  includes an impeller  28  mounted to a rotatable shaft  29  of a motor  30  of the motor section  16  for rotation therewith. The impeller  28  is generally planar and circular in shape. The impeller  28  has a hub portion  31  attached to the shaft  29  by suitable means (not shown). The impeller  28  also has a plurality of blade tips  32  extending radially from the hub portion  31  and disposed circumferentially thereabout. The impeller  28  has a peripheral ring portion  33  extending radially from the blade tips  32  to shroud the blade tips  32 . The impeller  28  is made of a rigid material such as plastic. 
     The pump section  14  also includes an inlet plate  34  disposed axially on one side of the impeller  28  and an outlet plate, generally indicated at  36 , disposed axially on the other side of the impeller  28 . The inlet plate  34  and outlet plate  36  are generally circular in shape. The inlet plate  34  and outlet plate  36  are enclosed by a housing  38  and fixed thereto. The inlet plate  34  and outlet plate  36  have an inlet or first recess  40  and an outlet or second recess  42 , respectively, located axially opposite the blade tips  32  adjacent to the peripheral ring portion  33  to form a flow channel  43  for a function to be described. The recesses  40  and  42  are annular and allow fuel to flow therethrough from an inlet port (not shown) to an outlet port (not shown) of the pump section  14 . The peripheral ring portion  33  of the impeller  28  forms an outside diameter (OD) sealing surface  46  on both axial sides thereof with the inlet plate  34  and outlet plate  36 . It should be appreciated that the impeller  28  rotates relative to the inlet plate  34  and outlet plate  36  and the inlet and outlet plates  34  and  36  are stationary. 
     The pump section  14  also includes a spacer ring  48  disposed axially between the inlet plate  34  and outlet plate  36  and spaced radially from the impeller  28 . The spacer ring  48  is fixed to the housing  38  and is stationary relative to the impeller  28 . The spacer ring  48  is generally planar and circular in shape. The spacer ring  48  has an inner diameter that is spaced from the outside diameter of the peripheral portion  33  of the impeller  28  to form an outside diameter (OD) cavity  50  between the inner diameter of the spacer ring  48  and an outside diameter of the peripheral ring portion  33  of the impeller  28 . It should be appreciated that fluid flows through both the inlet plate recess  40  and the outlet plate recess  42  and enters both recesses  40  and  42  at the inlet port region and exits out the outlet port region, 
     Referring to FIG. 2 through 5, either one or both the inlet plate  34  and/or outlet plate  36  are made of a composite material to improve the material abrasive wear resistance. The composite material is a plastic base resin material  54  and a wear insert  56  (FIG. 3) insert molded into the plastic base resin material  54 . The wear insert  56  is generally circular in shape. The wear insert  56  has the second recess  42  located on a lower surface thereof. The wear insert  56  has an annular first projection  58  extending upwardly from an upper surface thereof and circumferentially thereabout. The wear insert  56  has an annular second projection  60  extending upwardly from an upper surface thereof and circumferentially thereabout. The second projection  60  is spaced radially from the first projection  58  by a flow channel  62  extending circumferentially between the second recesses  42 . The wear insert  56  includes a central aperture  64  extending axially therethrough for a function to be described. The wear insert  56  is made of a high wear resistant material such as stainless steel, high carbon steel, ceramics, etc. that can be fabricated into a wear insert  56 . The wear insert  56  has a hardness equal to or greater than the hardness of an abrasive contaminant, for example quartz, R c 32 64, silica ingested by the fuel pump  12  during operation and causing abrasive wear. The wear insert  56  is formed or fabricated by conventional methods such as fine blanking, powdered metal sintering, powdered metal injection molding, ceramic injection molding, machined, etc. It should be appreciated that the wear insert  56  has a diameter less than a diameter of the base resin material  54 . It should also be appreciated that the wear insert  56  provides high strength, wear resistance, and a smooth contact and sealing surface against the impeller  28 . 
     The base resin material  54  is molded around the wear insert  56  to form a desired or predetermined shape. The base resin material  54  has a generally circular shape. The base resin material  54  has a cavity  66  extending axially and radially into a lower surface thereof to receive the wear insert  54 . The cavity  66  has an annular first recess  68  extending radially inwardly from an upper surface thereof and circumferentially thereabout to receive the first annular projection  58 . The cavity  66  has an annular second recess  70  extending radially from an upper surface thereof and circumferentially thereabout to receive the second annular projection  60 . The second recess  70  is spaced radially from the first recess  68  by a flow channel  62  extending circumferentially between the second recesses  42 . The base resin material  54  has a projection  72  extending axially through the central aperture  64  and an aperture  74  extending axially therethrough to allow the shaft  29  of the motor  30  to extend axially therethrough for connection to the impeller  28 . The base resin material  54  also includes at least one, preferably a plurality of vanes  76  extending upwardly from an upper surface thereof and spaced circumferentially. The base resin material  54  is made of a suitable plastic material such as a thermoformable plastic that can be molded over the wear insert  56 . The base resin material  54  has a hardness less than a hardness of the wear insert  56 . The base resin material  54  is molded or fabricated by conventional methods such as plastic injection molding, which are conventional and known in the art. The base resin material  54  is bonded to the wear insert  56  both mechanically and chemically. It should be appreciated that the overmoulding provides the complex shapes needed for high efficient pump sections and the mating features for the fuel pump  12 . 
     The present invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. 
     Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be practiced other than as specifically described.