Patent ID: 6769889
Filing Date: 2004-08-03
Classification: F04C,F05C

Abstract:
A gerotor fuel pump comprising:a housing including first and second side portions closing opposite sides of a center portion having a central opening that defines a circular rotor chamber between the side portions; inner and outer gear rotors rotatable within the rotor chamber on eccentric inner and outer rotor axes, the inner rotor having external teeth engaging mating internal tooth recesses of the outer rotor and configured to define a plurality of variable volume pumping chambers between and rotatable with the rotors within the rotor chamber; a drive shaft extending through and rotatably supported in and by one of the side portions, the drive shaft having a driving end terminating short of the other of the side portions and drivably engaging the inner rotor for rotation on the inner rotor axis, the outer rotor driven by the inner rotor and having a peripheral side rotatable proximate a radially inner side of the circular rotor chamber; inlet and outlet ports each extending through one of the first and second side portions and communicating with the pumping chambers in expansion and contraction portions, respectively, of their rotational paths within the rotor chamber; and a shadow port open to the rotor chamber in the side portion opposite to that of the outlet port, the shadow port being of similar area and configuration, and opposing the outlet port for balancing high fuel pressures on opposite sides of the rotors.