A filling member-less internal-gear unit has a casing with a bearing ring which is accommodated movably in a bore in the casing transversely with respect to its axis but non-rotatably. An internally toothed annular gear is rotatably mounted in the bearing ring and meshes with a pinion rotatably mounted in the casing. The bearing ring is pivotable relative to the bore in the casing about a pivot axis parallel to its axis. The pivot axis is so disposed that the ring portion of the bearing ring, which is associated with the engagement-free annular gear region, is moved at least approximately radially towards the pinion axis by the hydraulic pressure forces acting on the annular gear in the pressure chamber.