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Electric fuel pumpRelated Patent Categories: Pumps, Motor Driven, Electric Or Magnetic Motor, Rotary Motor And Rotary Nonexpansible Chamber Pump, Submersible TypeElectric fuel pump description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070122300, Electric fuel pump. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an electric fuel pump, where fuel in a fuel tank is pressurized, and the pressurized fuel is supplied toward a fuel injection valve. The electric fuel pump is used for a fuel supply device of an internal combustion engine of a vehicle, a two-wheeled vehicle, a general-purpose machine, an engine for marine use or the like. [0003] 2. Description of the Conventional Art [0004] A conventional electric fuel pump is indicated in Japanese Patent Publication No. 8-9995. [0005] This electric fuel pump is explained in FIG. 2. Reference numeral 30 is a cylindrical housing having openings at both ends, and formed with a metallic material such as iron, aluminum or the like. The housing 30 has a pump part P provided at a lower end thereof, a discharge part T provided at an upper end thereof, and a motor part M provided at a middle part thereof. [0006] The pump part P has a pump chamber 33 formed with a pump casing 31 and a pump cover 32, and a regenerative pump type impeller 34 is rotatably provided in the pump chamber 33. [0007] Further, the pump cover 32 has a pump suction passage 35a, which is formed to open downward and extend into the pump chamber 33. The pump casing 31 has the pump discharge passage 35b opening into the pump chamber 30 from the pump chamber 33. [0008] As mentioned above, the lower end opening of the housing 30 is closed with the pump casing 31 and the pump cover 32, and the pump part P is formed at this closed portion. [0009] The motor part M comprises an armature 36 and a field magnet 37. A lower end of a rotary shaft 38 provided at a center of the armature 36 is rotatably supported by the pump casing 31 through a bearing 39a. An upper end of the rotary shaft 38 is rotatably supported by a bearing holding member 40 through a bearing 39b. [0010] Then, the lower end of the rotary shaft 38 is engaged in an engaging hole 34a of the impeller 34, and the rotation of the rotary shaft 38 is transmitted to the impeller 34. [0011] Further, the upper end opening of the housing 30 is closed with the bearing holding member 40 and a housing cover 41, which is provided on the upper side of the bearing holding member 40. A vertical hole 40a of the bearing holding member 40 has a brush 42 provided movably upward and downward. A lower end 42a of the brush 42 is pressed by a spring 43, and is elastically energized onto a planar commutator 36a of the armature 36. [0012] The brush is electrically connected with a terminal rod 44 projected upwardly from the housing cover 41 through a choke coil 45, a brush presser plate 46 and a pig tail 47. [0013] Further, 48 is a discharge passage, which is projected from the housing cover 41 to open upwardly. The discharge passage 48 has a check valve 49 for preventing downward fuel flowing. [0014] Thereby, electric current is supplied to the armature 36 from the terminal rod 44 through the choke coil 45, the brush presser plate 46, the pig tail 47, the brush 42 and the planar commutator 36a, to thereby rotate the armature 36 in the housing 30, and the rotation of the armature 36 is transmitted to impeller 34 through the rotary shaft 38. [0015] Further, the impeller 34 is rotated in the pump chamber 33, to thereby generate a pressure difference in the front and the rear of a blade groove on an outer circumference of the impeller. Such the pressure difference is repeatedly generated in multiple blade grooves, to thereby suck the fuel into the pump chamber 33 from the pump suction passage 35a, and the fuel pressurized in the pump chamber 33 is discharged into the housing 30 from the pump discharge passage 35b. Further, the discharged fuel is passed around the motor part M and discharged to a fuel pipe extending to the outside through the discharge passage 48. SUMMARY OF THE INVENTION [0016] Such a conventional electric fuel pump is used as the fuel supply device of an engine for marine use, such as an engine for outboard motor, an engine for inboard motor or the like. Thus, sea water may be entered into a gasoline fuel to be used in such the engine for marine use. [0017] When the fuel containing the sea water is discharged into the housing 30 from the pump chamber 33 and contacted with a part between electrodes of the motor part M, the fuel is bonded with a metal ion such as calcium, magnesium or the like, which is dissolved in the sea water, to thereby generate calcium or the like, and the generated impurities are supplied toward the fuel injection valve from the discharge passage 48 through the fuel pipe. [0018] On the other hand, the fuel pipe has a filter for removing such impurities. However, when calcium or the like is generated to be discharged, it is necessary to increase the maintenance work frequency for the filter. [0019] Further, when the fuel containing a sea water is contacted with an inner conductive wire of the pig tail 47 or the like in the housing 30, electric current flows between positive and negative to thereby generate an electrolysis reaction. Then, the inner conductive wire containing a positive terminal is dissolved to promote corrosion. [0020] Further, in the engine stopping state, the planar commutator 36a other than a contacting part between the planar commutator 36a and the lower end 42a of the brush 42 is directly exposed in the fuel containing the sea water. Thus, in preservation of the engine for a long period, an oxide film is formed on the planar commutator 36a other than the contacting part, and when the engine is started after stopping for a long time, trouble may be caused to the starting of the motor part M. [0021] Furthermore, it is a tendency that alcohol is blended in the gasoline as an oxygen-containing fuel to be used from the viewpoint of an environment issue in recent years. In such fuel, the mixing of the gasoline and the sea water is promoted by alcohol, and the above problems are also promoted, so that it is not preferable. [0022] Then, in order to solve the above problems, the structure illustrated in FIG. 3 is considered, wherein the fuel discharged from the pump part is not contacted with a part of the motor part by shutting off the pump part provided in the housing from the motor part. Continue reading about Electric fuel pump... Full patent description for Electric fuel pump Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Electric fuel pump patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. 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