Fuel pump

Abstract

A fuel pump includes a housing having a cavity. The cavity has a rear surface, and a drive gear and driven gear are disposed in the cavity and in mesh with one another for pressurizing fluid. A floating wear plate and a fixed wear plate are disposed in the cavity and are in contact with the drive gear and the driven gear. A flow orifice is formed as part of the floating wear plate, and a portion of the pressurized fluid flows through the flow orifice to an area between the rear surface of the cavity and the floating wear plate, causing the floating wear plate to apply force to the drive gear and driven gear, and causing the drive gear and driven gear to apply force to the fixed wear plate, thereby compensating for any wear of the drive gear, driven gear, and wear plates.

1 . A fuel pump, comprising:
 a housing having a cavity, said cavity having a rear surface;   a drive gear disposed in said cavity;   a driven gear disposed in said cavity and in mesh with said drive gear for pressurizing fluid flowing into said housing;   a floating wear plate having an inner side adjacent and in contact with said drive gear and said driven gear;   a fixed wear plate having an inner surface adjacent and in contact with said drive gear and said driven gear; and   a flow orifice formed as part of said floating wear plate such that a portion of said pressurized fluid flows through said flow orifice and between said rear surface of said cavity and said floating wear plate, causing said floating wear plate to apply force to said drive gear and said driven gear, and therefore causing said drive gear and said driven gear to apply force to said fixed wear plate, thereby compensating for any wear of said drive gear, said driven gear, said floating wear plate, and said fixed wear plate.   
     
     
         2 . The fuel pump of  claim 1 , further comprising:
 a groove formed on an outer periphery of said floating wear plate; and   a seal disposed in said groove formed on said outer periphery of said floating wear plate, primarily to seal the wear plate to the gear cavity wall, but also said seal operable to substantially prevent pressurized fluid from flowing around the outer periphery of said floating wear plate.   
     
     
         3 . The fuel pump of  claim 2 , further comprising a circumferential wall surrounding said drive gear and said driven gear, said drive gear and said driven gear being in minimal clearance with said circumferential wall, said seal is in contact with said circumferential wall to substantially prevent pressurized fluid from flowing around the outer periphery of said floating wear plate. 
     
     
         4 . The fuel pump of  claim 1 , further comprising:
 a drive shaft extending through a bore formed as part of said housing, said drive gear mounted on said drive shaft; and   an idler shaft extending into a recess formed as part of said housing, said driven gear mounted on said idler shaft.   
     
     
         5 . The fuel pump of  claim 4 , further comprising a non-moving pressure isolation sleeve circumscribing said drive shaft, said pressure isolation sleeve partially disposed in said bore and partially disposed in said gear cavity for substantially preventing fluid from flowing into said bore. 
     
     
         6 . The fuel pump of  claim 5 , said pressure isolation sleeve further comprising:
 a first groove formed as a part of said pressure isolation sleeve disposed in said bore;   a reduced diameter formed as a part of said pressure isolation sleeve disposed in said gear cavity;   a first seal disposed in said first groove for preventing fluid from flowing into said bore; and   a second seal disposed in said reduced diameter and a receiver groove formed on said outer side of said floating wear plate for preventing fluid from flowing around a portion of said drive shaft extending through said floating wear plate.   
     
     
         7 . The fuel pump of  claim 1 , further comprising:
 an inlet formed as part of said housing;   an inlet notch formed on said inner side of said floating wear plate such that fluid flowing into said housing from said inlet flows between said inlet notch formed as part of said floating wear plate as well as said drive gear and said driven gear; and   an inlet notch formed on said inner surface of said fixed wear plate such that fluid flowing into said housing from said inlet flows between said inlet notch formed as part of said fixed wear plate as well as said drive gear and said driven gear.   
     
     
         8 . The fuel pump of  claim 1 , further comprising:
 an outlet formed as part of said housing;   an outlet notch formed on said inner side of said floating wear plate such that said fluid pressurized by said drive gear and said driven gear flows between said outlet notch formed as part of said floating wear plate as well as said drive gear and said driven gear to said outlet of said housing; and   an outlet notch formed on said inner surface of said fixed wear plate such that said fluid pressurized by said drive gear and said driven gear flows between said outlet notch formed as part of said fixed wear plate as well as said drive gear and said driven gear to said outlet of said housing, said drive gear and said driven gear operable for pressurizing said fluid.   
     
     
         9 . A fuel pump, comprising:
 a housing having a cavity, said cavity having a rear surface and a circumferential wall;   a drive gear disposed in said cavity;   a driven gear disposed in said cavity and in mesh with said drive gear for pressurizing fluid flowing into said housing;   a floating wear plate having an inner side adjacent and in contact with said drive gear and said driven gear;   a groove formed on the outer periphery of said floating wear plate;   a seal disposed in said groove formed on said outer periphery of said floating wear plate such that said seal is in contact with said circumferential wall for substantially preventing fluid flow around the outer periphery of said floating wear plate;   a fixed wear plate having an inner surface adjacent and in contact with said drive gear and said driven gear; and   a flow orifice formed as part of said floating wear plate such that a portion of said pressurized fluid flows through said flow orifice to pressurize the space between said rear surface of said cavity and said floating wear plate, causing said floating wear plate to apply pressure to said drive gear and said driven gear, and causing said drive gear and said driven gear to apply pressure to said fixed wear plate, thereby compensating for any wear of said drive gear, said driven gear, said floating wear plate, and said fixed wear plate.   
     
     
         10 . The fuel pump of  claim 9 , further comprising:
 an inlet formed as part of said housing;   an inlet notch formed on said inner side of said floating wear plate such that fluid flowing into said housing from said inlet flows between said inlet notch formed as part of said floating wear plate as well as said drive gear and said driven gear; and   an inlet notch formed on said inner surface of said fixed wear plate such that fluid flowing into said housing from said inlet flows between said inlet notch formed as part of said fixed wear plate as well as said drive gear and said driven gear.   
     
     
         11 . The fuel pump of  claim 9 , further comprising:
 an outlet formed as part of said housing;   an outlet notch formed on said inner side of said floating wear plate such that said fluid pressurized by said drive gear and said driven gear flows between said outlet notch formed as part of said floating wear plate as well as said drive gear and said driven gear to said outlet of said housing; and   an outlet notch formed on said inner surface of said fixed wear plate such that said fluid pressurized by said drive gear and said driven gear flows between said outlet notch formed as part of said fixed wear plate as well as said drive gear and said driven gear to said outlet of said housing, said drive gear and said driven gear operable for pressurizing said fluid.   
     
     
         12 . The fuel pump of  claim 11 , said flow orifice is formed as part of said outlet notch formed on said inner side of said floating wear plate. 
     
     
         13 . The fuel pump of  claim 9 , further comprising:
 a drive shaft extending through a bore formed as part of said housing, said drive gear mounted on said drive shaft; and   an idler shaft partially extending into a recess formed as part of said housing, said driven gear mounted on said idler shaft such that said drive gear is in mesh with said driven gear.   
     
     
         14 . The fuel pump of  claim 13 , further comprising a non-moving pressure isolation sleeve circumscribing said drive shaft, said pressure isolation sleeve partially disposed in said bore and partially disposed in said gear cavity for substantially preventing fluid from flowing into said bore. 
     
     
         15 . The fuel pump of  claim 14 , said pressure isolation sleeve further comprising:
 a first groove formed as a part of said non moving-pressure isolation sleeve disposed in said bore;   a reduced diameter formed as a part of said non-moving pressure isolation sleeve disposed in said gear cavity;   a first seal disposed in said first groove for preventing fluid from flowing into said bore; and   a second seal disposed in said notch and a receiver groove formed on said outer side of said floating wear plate for preventing fluid from flowing around a portion of said drive shaft extending through said floating wear plate.   
     
     
         16 . The fuel pump of  claim 9 , wherein said drive gear and said driven gear are at minimal clearance with said circumferential wall of said housing. 
     
     
         17 . A fuel pump, comprising:
 a housing having an inlet, an outlet, and a gear cavity, said gear cavity having a rear surface and a circumferential wall;   a drive gear mounted on a drive shaft, said drive gear disposed in said gear cavity, said drive shaft extending into a bore formed as part of said housing;   a driven gear mounted on an idler shaft, said driven gear disposed in said gear cavity and in mesh with said drive gear, said circumferential wall substantially surrounding said drive gear and said driven gear such that said drive gear and said driven gear are in minimal clearance with said circumferential wall;   a floating wear plate having an inner side adjacent and in contact with said drive gear and said driven gear;   a groove formed on an outer periphery of said floating wear plate;   a side seal disposed in said groove and in contact with said circumferential wall of said gear cavity, primarily to seal the wear plate to the gear cavity walls, but also to substantially prevent pressurized fluid from flowing around the outer periphery of said floating wear plate;   a fixed wear plate having an inner surface adjacent and in contact with said drive gear and said driven gear;   a flow orifice formed as part of said floating wear plate such that fluid flows through said pump inlet and into said gear cavity and said drive gear and said driven gear rotate to create a pumping action to force a portion of said fluid out of said outlet, and a portion of fluid through said flow orifice to pressurize said gear cavity between said floating wear plate and said rear surface of said gear cavity, maintaining said floating wear plate in contact with said drive gear and said driven gear, as well as maintaining said fixed wear plate in contact with said drive gear and said driven gear to compensate for wear of said floating wear plate, said fixed wear plate, said drive gear, and said driven gear.   
     
     
         18 . The fuel pump of  claim 17 , further comprising:
 an inlet notch formed on said inner side of said floating wear plate such that fluid flowing into said housing from said inlet flows between said inlet notch formed as part of said floating wear plate as well as said drive gear and said driven gear;   an inlet notch formed on said inner surface of said fixed wear plate such that fluid flowing into said housing from said inlet flows between said inlet notch formed as part of said fixed wear plate as well as said drive gear and said driven gear;   an outlet notch formed on said inner side of said floating wear plate such that said fluid pressurized by said drive gear and said driven gear flows between said outlet notch formed as part of said floating wear plate as well as said drive gear and said driven gear to said outlet of said housing; and   an outlet notch formed on said inner surface of said fixed wear plate such that said fluid pressurized by said drive gear and said driven gear flows between said outlet notch formed as part of said fixed wear plate as well as said drive gear and said driven gear to said outlet of said housing, said drive gear and said driven gear operable for pressurizing said fluid.   
     
     
         19 . The fuel pump of  claim 17 , further comprising a non-moving pressure isolation sleeve circumscribing said drive shaft, said non-moving pressure isolation sleeve partially disposed in said bore and partially disposed in said gear cavity for substantially preventing fluid from flowing into said bore. 
     
     
         20 . The fuel pump of  claim 19 , said non-moving pressure isolation sleeve further comprising:
 a first groove formed as a part of said non-moving pressure isolation sleeve disposed in said bore;   a reduced diameter formed as a part of said non-moving pressure isolation sleeve disposed in said gear cavity;   a first seal disposed in said first groove for preventing fluid from flowing into said bore; and   a second seal disposed in said notch and a receiver groove formed on said outer side of said floating wear plate for preventing fluid from flowing around a portion of said drive shaft extending through said floating wear plate.