US Patent 7670122 Gerotor pump

A gerotor pump includes an outer rotor having a first toothed surface and lobes that extend inwards. An inner rotor is eccentrically aligned relative to the outer rotor and includes a second toothed surface and lobes that extend outwards. Planetary gears are located between the outer rotor and the inner rotor. Each planetary gear has a third toothed surface that intermeshes with the first toothed surface and the second toothed surface.