Patent ID: 6716008
Filing Date: 2004-04-06
Classification: F04C

Abstract:
A displacement machine in the form of an eccentric screw pump or motor (1) comprising a stator 3 having a tube-shaped jacket (22), said jacket (22) having a connector (26) at one end for enabling connection of the jacket (22) to another part (2, 5), said jacket having an elastic, flexible coating (32) on an inner side thereof which forms a helical bore over a region of its length, said helical bore forming an inner wall which has a cross sectional profile transverse to a longitudinal axis of the tube shaped jacket (22) defined by an edge (44) having a wave-shaped profile such that the bore defines helical teeth (37) which are separated from each other by tooth gaps (38), said inner wall cross sectional profile of said bore being formed with a plurality of additional waves, (41) each of which extends helically in a longitudinal direction and whose dimensions in both the circumferential and radial directions are smaller than the dimensions of said teeth (37) of said bore, each tooth defined by said wave-shaped profile being formed with at least one of said additional waves (41), a rotor (4) disposed within said bore for relative rolling movement, and said rotor (4) being in the form of a spiral-toothed pinion with one or more teeth (35) and tooth gaps (36) which are disposed within the bore defined by said coating (32) such that said rotor can roll in the bore with the teeth (35) of the rotor engaging the tooth gaps (38) of the coating (32).