Abstract: A fuel pump includes an output shaft of a motor and an impeller configured to rotate integrally with the output shaft. An outer periphery of the output shaft includes a first flat portion for engaging with the impeller. The impeller includes a through hole at a center thereof, the through hole being larger than an outer diameter of the output shaft and including a second flat portion for engaging with the output shaft. In this fuel pump, when the output shaft and the impeller are arranged coaxially, spots exist which have different lengths of a gap between the first flat portion and the second flat portion in a rotational axis direction of the output shaft.

Abstract: Fuel pump (10) may comprise a casing (18) and a substantially disc-shaped impeller (20) which is rotatably disposed within the casing (18). A first group of concavities (21a) may be formed in a lower face of the impeller (20). A second group of concavities (20a) may be formed in an upper face of the impeller (20). A first groove (30) may be formed in the inner face of the casing (18) opposite the upper face of the impeller (20). The first groove (30) is formed in a region opposite the first group of concavities (21a) and extending from an upstream end to a downstream end. A second groove (24) may be formed in the inner face of the casing opposite the lower face of the impeller (20). The second groove (24) is formed in a region opposite the second group of concavities (20a) and extending from an upstream end to a downstream end.

Abstract: The brush device is provided with a brush, a brush holder, and a biasing member. The brush holder has an insertion hole in which the brush is inserted. The biasing member biases the brush toward the sliding surface. The sliding surface is approximately perpendicular to the rotational axis of the commutator. The brush is inclined such that an end of the brush on a side of the commutator is positioned on a forward side of the other end of the brush with respect to a rotational direction of the commutator. A surface of the brush on the side of the commutator is approximately parallel with the sliding surface.

Abstract: A fuel injection port 21 formed in a seat 20 is opened and closed by a movable valve 14 supported by a flat spring 16. The movable valve 14 is biased by an elastic force of a coil spring 26 in a direction that closes the fuel injection port 21. When electric power is supplied to a solenoid coil 4, the movable valve 14 is moved to a direction that opens the fuel injection port 21 as a result of an electromagnetic attraction force between a magnetic circuit M for generating an electromagnetic attraction force and the movable valve 14. Air gaps G0, G1 and G2 are formed within the fuel injection port and permeance ratios between the air gaps may be set to optimal valves.

Abstract: A fuel injection port 21 formed in a seat 20 is opened and closed by a movable valve 14 supported by a flat spring 16. The movable valve 14 is biased by an elastic force of a coil spring 26 in a direction that closes the fuel injection port 21. When electric power is supplied to a solenoid coil 4, the movable valve 14 is moved to a direction that opens the fuel injection port 21 as a result of an electromagnetic attraction force between a magnetic circuit M for generating an electromagnetic attraction force and the movable valve 14. Air gaps G0, G1 and G2 are formed within the fuel injection port and permeance ratios between the air gaps may be set to optimal values.