Patent ID: 6872061

Claim:
A method for manufacturing a stator of a Moineau-type gear pump, this stator comprising a stator cavity running axially overall inside an elongate body, the method consisting in manufacturing said stator cavity from a rigid-walled metal tube that is cylindrical of revolution, the method comprising the following steps: a preliminary mechanical-forming step during which said metal tube that is cylindrical of revolution is deformed so as to preform a rough form that internally is substantially helical in shape and approximates to the shape and dimensions of the desired stator cavity, then a definitive-forming step during which said rough form is subjected to a hydroforming process, performed inside a hydroforming chamber, on a molding form to obtain a tubular metal element forming a stator cavity with its shape and its exact interior dimensions such that once the stator has been assembled with a rotor, a positive clearance with the rotor is defined, and finally a step of mounting the tubular metal element that forms the stator cavity inside an outer casing forming a housing, with at least the ends of the tubular metal element being joined to said casing.