Abstract: A fuel pump unit includes a suction filter and a fuel pump. The fuel pump includes: a rotatable shaft placed along a rotational axis; a rotor portion that rotates in response to rotation of the rotatable shaft; a suction hole portion, through which the fuel is suctioned into an inside of a rotor receiving chamber; and an outer peripheral wall that surrounds the suction hole portion. The suction filter includes: a filter element that filters the fuel and conducts the filtered fuel into an inside space; and a columnar hole portion having an inner peripheral wall, while the outer peripheral wall and the inner peripheral wall are fitted with each other, so that the columnar hole portion communicates between the inside space and the suction hole portion. The columnar hole portion is placed such that the rotational axis extends on an inner side of the inner peripheral wall.

Abstract: A fuel pump is connected to a suction filter which is provided with a filter connecting portion having a cylindrical hole and a projecting portion protruding radially inward from an inner peripheral wall of the cylindrical hole. The fuel pump suctions the fuel filtered by the suction filter. The fuel pump is provided with a suction port having multiple suction openings at a side of the suction filter so as to suction the fuel therethrough, and a pump connecting portion provided at outer side of the multiple suction openings and connected with the filter connecting portion. The pump connecting portion has an outer peripheral wall of which outer shape corresponds with a shape of the inner peripheral wall, and a dent portion denting inward from the outer peripheral wall, which the projecting portion is engaged with.

Abstract: An inner gear includes: sliding surface parts that are provided annularly at an outer peripheral part including a plurality of outer teeth on both sides of the inner gear in its axial direction and that slide on a pump housing; recessed parts that are respectively provided radially inward of the sliding surface parts to respectively form fuel chambers, into which fuel flows, between the recessed parts and the pump housing; and a communication hole that communicates between the recessed parts. The inner gear further includes an inclined surface part that is provided at an edge portion of a communicating edge portion on a rotation advance side of the inner gear, to avoid an adjacent part adjacent to an inner peripheral edge portion of each of the sliding surface parts and that is inclined further toward a rear side in a direction to a central part of the communication hole.

Abstract: An outer gear and an inner gear expand and contract volume of pump chambers formed between both the gears, and rotate to suction fuel into the pump chambers and then discharge fuel from the pump chambers sequentially. The inner gear includes an insertion hole that is depressed along its axial direction. A joint member includes a main body portion that is fitted to a rotary shaft, a foot portion that extends from the main body portion along the axial direction and is inserted in the insertion hole with a clearance therebetween, and a protruding portion that protrudes from the foot portion toward a rotation progress side of the inner gear and has its width in the axial direction further narrowed toward a top portion of the protruding portion.

Abstract: A casing of a housing of a fuel pump has a bearing surface that rotatably supports an inner gear in an axial direction from a motor side while a plain bearing extends through the bearing surface. The plain bearing includes: an inner-peripheral-side step that is stepped by increasing an inner diameter of the plain bearing on a counter-motor side of the inner-peripheral-side step in the axial direction; and an outer-peripheral-side step that is stepped by increasing an outer diameter of the plain bearing on the motor side of the outer-peripheral-side step at a position that is on the motor side of the bearing surface in the axial direction.

Abstract: A fuel pump includes: an outer gear having a plurality of inner teeth; an inner gear having a plurality of outer teeth and eccentrically meshing with the outer gear; and a pump housing that defines a cylindrical gear housing chamber housing the outer gear and the inner gear to be rotatable. The outer gear and the inner gear rotate, while expanding and contracting a volume of a plurality of pump chambers formed between the outer gear and the inner gear, to sequentially draw fuel into and discharge from the pump chamber. An inner circumference part of the pump housing has a radially-inside corner part opposing a radially-outside corner part of an outer circumference part of the outer gear, and the pump housing has an annular groove formed in an annular shape all around the radially-inside corner part.

Abstract: A pump housing includes: a slide surface, along which inner and outer gears are slid; a suction guide passage, which is recessed from the slide surface and guides the fuel at a suction side; a discharge passage, which is recessed from the slide surface-and guides the fuel at a discharge side; and a communication groove, which is recessed from the slide surface and is shaped into an arcuate form that extends along a circumcircle of the inner gear. The communication groove is communicated with the suction groove and the discharge passage through two opposite groove end parts, respectively, of the communication groove.

Abstract: The pump housing includes a pair of sliding surfaces clamping the outer and inner gears from both their sides to allow both the gears to slide on the sliding surfaces, a suction port part suctioning fuel from outside into inside of the gear accommodation chamber, and a discharge port part discharging fuel from inside into outside of the gear accommodation chamber. At least one of the suction port part and the discharge port part includes an elongated groove that is depressed from the corresponding sliding surface and extends along a circumferential direction of the pump housing in a region opposed to the pump chambers, opening bores that open on the elongated groove from outside of the gear accommodation chamber, and ribs each of which is arranged between the corresponding adjacent two opening bores. The opening bores and the ribs are arranged alternately along an extending direction of the elongated groove.

Abstract: A suction side end part of a suction guide passage and a discharge side end part of a discharge guide passage are opposed to each other with a gap therebetween. At a deviation angle at which contraction of a pump chamber starts, an outer peripheral part of the discharge side end part is formed along an inner tooth, and an inner peripheral part of the discharge side end part is formed along an outer tooth. A working tool that rotates and cuts circularly is moved around on a pump housing in a single continuous line to form an outline of the discharge guide passage, thereby forming the discharge guide passage. The working tool is moved around on the pump housing in a single continuous line to form an outline of the suction guide passage, thereby forming the suction guide passage.

Abstract: A fuel pump includes: an outer gear; an inner gear that is meshed with the outer gear and includes a receiving hole; a rotatable shaft; a contact portion that is formed to be contactable with the receiving hole; and a pump housing that rotatably receives the outer gear and the inner gear and includes a first housing component and a second housing component, between which the inner gear is held in the axial direction. At least one of the receiving hole and the contact portion includes a tilt surface, which is tilted relative to the axis direction. When the rotatable shaft is rotated to a drive rotation side, the receiving hole contacts the contact portion through the tilt surface, so that the receiving hole is urged in a circumferential direction and is also urged toward the first housing component in the axial direction.

Abstract: A casing of a housing of a fuel pump has a bearing surface that rotatably supports an inner gear in an axial direction from a motor side while a plain bearing extends through the bearing surface. The plain bearing includes: an inner-peripheral-side step that is stepped by increasing an inner diameter of the plain bearing on a counter-motor side of the inner-peripheral-side step in the axial direction; and an outer-peripheral-side step that is stepped by increasing an outer diameter of the plain bearing on the motor side of the outer-peripheral-side step at a position that is on the motor side of the bearing surface in the axial direction.

Abstract: A fuel pump unit includes a suction filter and a fuel pump. The fuel pump includes: a rotatable shaft placed along a rotational axis; a rotor portion that rotates in response to rotation of the rotatable shaft; a suction hole portion, through which the fuel is suctioned into an inside of a rotor receiving chamber; and an outer peripheral wall that surrounds the suction hole portion. The suction filter includes: a filter element that filters the fuel and conducts the filtered fuel into an inside space; and a columnar hole portion having an inner peripheral wall, while the outer peripheral wall and the inner peripheral wall are fitted with each other, so that the columnar hole portion communicates between the inside space and the suction hole portion. The columnar hole portion is placed such that the rotational axis extends on an inner side of the inner peripheral wall.

Abstract: A fuel pump is connected to a suction filter which is provided with a filter connecting portion having a cylindrical hole and a projecting portion protruding radially inward from an inner peripheral wall of the cylindrical hole. The fuel pump suctions the fuel filtered by the suction filter. The fuel pump is provided with a suction port having multiple suction openings at a side of the suction filter so as to suction the fuel therethrough, and a pump connecting portion provided at outer side of the multiple suction openings and connected with the filter connecting portion. The pump connecting portion has an outer peripheral wall of which outer shape corresponds with a shape of the inner peripheral wall, and a dent portion denting inward from the outer peripheral wall, which the projecting portion is engaged with.

Abstract: The pump housing includes a pair of sliding surfaces clamping the outer and inner gears from both their sides to allow both the gears to slide on the sliding surfaces, a suction port part suctioning fuel from outside into inside of the gear accommodation chamber, and a discharge port part discharging fuel from inside into outside of the gear accommodation chamber. At least one of the suction port part and the discharge port part includes an elongated groove that is depressed from the corresponding sliding surface and extends along a circumferential direction of the pump housing in a region opposed to the pump chambers, opening bores that open on the elongated groove from outside of the gear accommodation chamber, and ribs each of which is arranged between the corresponding adjacent two opening bores. The opening bores and the ribs are arranged alternately along an extending direction of the elongated groove.

Abstract: A fuel pump includes rotors that rotate, a pump housing that defines a rotor housing chamber that rotatably houses the rotors, and an outer circumferential side housing that includes a cylindrical portion formed in a cylindrical shape that surrounds the pump housing from an outer circumferential side and a narrowing potion having that narrows down with respect to the cylindrical portion. The fuel pump sucks fuel into the rotor housing chamber and then discharges the fuel due to the rotor rotating. A pump cover of the pump housing includes an inlet port that sucks fuel into the rotor housing chamber, and a sliding surface portion on which the rotors slide. An outer circumferential portion of the pump cover includes a joining portion joined to the narrowing portion, and a recessed portion that is recessed adjacent to the joining portion, the recessed portion allowing the outer circumferential portion to elastically deform.

Abstract: A fuel pump includes rotors that rotate, a pump housing that defines a rotor housing chamber that rotatably houses the rotors, and an outer circumferential side housing that includes a cylindrical portion formed in a cylindrical shape that surrounds the pump housing from an outer circumferential side and a narrowing potion having that narrows down with respect to the cylindrical portion. The fuel pump sucks fuel into the rotor housing chamber and then discharges the fuel due to the rotor rotating. A pump cover of the pump housing includes an inlet port that sucks fuel into the rotor housing chamber, and a sliding surface portion on which the rotors slide. An outer circumferential portion of the pump cover includes a joining portion joined to the narrowing portion, and a recessed portion that is recessed adjacent to the joining portion, the recessed portion allowing the outer circumferential portion to elastically deform.

Abstract: A fuel pump includes an inner rotor, an outer rotor, a casing, and a housing. The inner rotor includes outward teeth. The outer rotor includes inward teeth geared with the outward teeth. The casing houses the inner rotor and the outer rotor, and forms a variable capacity pump chamber between the inward teeth and the outward teeth. The housing is formed in a cylindrical shape and includes a cylindrical inner portion, the casing being press fit into the cylindrical inner portion. A recessed portion is formed at a predetermined position in a circumferential direction of an outer circumferential surface of the casing, the recessed portion being recessed toward a radial direction center of the outer circumferential surface.

Abstract: A fuel pump includes: an outer gear having a plurality of inner teeth; an inner gear having a plurality of outer teeth and eccentrically meshing with the outer gear; and a pump housing that defines a cylindrical gear housing chamber housing the outer gear and the inner gear to be rotatable. The outer gear and the inner gear rotate, while expanding and contracting a volume of a plurality of pump chambers formed between the outer gear and the inner gear, to sequentially draw fuel into and discharge from the pump chamber. An inner circumference part of the pump housing has a radially-inside corner part opposing a radially-outside corner part of an outer circumference part of the outer gear, and the pump housing has an annular groove formed in an annular shape all around the radially-inside corner part.

Abstract: A pump housing includes: a slide surface, along which inner and outer gears are slid; a suction guide passage, which is recessed from the slide surface and guides the fuel at a suction side; a discharge passage, which is recessed from the slide surface-and guides the fuel at a discharge side; and a communication groove, which is recessed from the slide surface and is shaped into an arcuate form that extends along a circumcircle of the inner gear. The communication groove is communicated with the suction groove and the discharge passage through two opposite groove end parts, respectively, of the communication groove.

Abstract: A pump housing receives an outer rotor and an inner rotor. A joint member couples between a rotatable shaft and the inner rotor to transmit a rotational torque from the rotatable shaft to the inner rotor. A radial bearing is shaped into a cylindrical tubular form. A cylindrical inner peripheral surface of the radial bearing rotatably and slidably supports the rotatable shaft. A cylindrical outer peripheral surface of the radial bearing rotatably and slidably supports an inner peripheral surface of the inner rotor. A lubrication groove is formed in the cylindrical outer peripheral surface of the radial bearing and accumulates fluid, which is present in an inside of the pump housing.