Internal gear pump with recesses on the gear bearing surfaces

摘要

A positive-displacement pump, in particular for use in machines for dispensing fluids, comprises two elements that are rotatable with respect to one another and which mesh with one another (20, 30), each of them being rotatably mounted in the pump with centered coupling without interference with a corresponding centering body (18, 11a). At least one of the two above-mentioned rotatable elements has a plurality of undercut regions (26, 34, 35) at the location of the centering walls. The undercut regions (26, 34, 35) comprise a wall portion which is spaced with respect to the facing wall of the respective centering body.