Gear pump with eccentric pinion meshing with rotary gear ring - using intermediate pressure to balance radial forces on ring and pinion

摘要

The hydraulic gear pump for liquids comprises a housing contg. a rotary gear ring with internal teeth meshing with an eccentric pinion having at least two teeth less. The ring has radial ports (27) between its teeth and is outwardly engaged by a resilient pressure member (6), integral with the housing and pressurised from outside by an intermediate pressure above inlet pressure via a chamber (28) between the ring and pressure member. The member (6) is arranged diametrically opposite to the area of deepest tooth engagement, in which area the housing contains the pump outlet (21) pressure. This high-pressure region (29) is separated from the chamber so that the other chambers (35,36,28) always communicate with the intermediate pressure area (a) between the gears where there is no tooth engagement.PS.