Patent ID: 7950905

Claim:
A high pressure radial piston fuel pump having an hydraulic head with two individual radial pumping pistons and associated pumping chambers, annularly spaced around a cavity in the head where a rotating eccentric drive member with associated actuation ring are situated, characterized in that a rolling interaction is provided between the actuation ring and the inner ends of the pistons for intermittent actuation, and relative rotation is provided between the actuation ring and the drive member each piston having a piston bore that has a centerline that intersects the actuation ring but is offset (X) from the drive axis as viewed in cross section perpendicularly to the drive axis, and the piston bore centerlines are parallel to each other but offset (Y) from each other as viewed in longitudinal section along the drive axis, wherein the hydraulic head defines the central cavity for receiving a rotatable drive shaft longitudinally disposed along a drive axis passing through the cavity; the drive member is cylindrical and is rigidly carried by and offset from the drive shaft for eccentric rotation in the cavity about the drive axis as the drive shaft rotates; the actuation ring is substantially cylindrical and is annularly mounted around the drive member; bearing means are located between the drive member and the actuation ring, whereby the actuation ring is supported for freely rotating about the drive member; each piston is situated respectively in a piston bore for free reciprocation therein, each said piston having an actuated end in the cavity and a pumping end remote from the cavity, wherein the pumping end cooperates with the piston bore to define a pumping chamber; a piston shoe rigidly extends from the actuated end of each piston, and has an actuation surface for maintaining contact with the actuation ring during rotation of the drive shaft; means are provided for biasing each piston toward the cavity; a feed fuel valve train is provided for delivering charging fuel through an inlet passage in the head at a feed pressure to the pumping chamber; a high pressure valve train is provided for delivering pumped fuel to a discharge passage in the head at a high pressure from the pumping chamber; whereby during one complete rotation of the drive shaft, each pumping chamber undergoes a charging phase wherein the associated piston is retracted toward the cavity by the means for biasing, thereby increasing the volume of the pumping chamber to accommodate an inlet quantity of fuel from the inlet valve train, and a discharging phase wherein said associated piston is actuated away from the cavity by the actuation ring, thereby decreasing the volume of the pumping chamber and pressurizing the quantity of fuel for discharge through said discharge valve train.