Fluid transfer pipe with corrugated portion(s) and method for manufacturing same

Fluid transfer pipe for filling a cooling circuit of a motor vehicle heat engine, comprising at least one single-layer or multilayer corrugated bendable portion which is based on at least one thermoplastic material and which comprises a succession of radial reliefs which are axially spaced so as to form hollows between them,

• each relief having two frontal regions linked together by an intermediate region, the frontal regions of each relief each having one and the same overall polygonal contour defining at least three straight sections which are interlinked by rounded sections and which each have a length greater than that of each rounded section,
• said at least one corrugated portion being molded from two hemicylindrical shells of a mold along a single axial stripping plane,
• wherein, at the level of said rounded sections of each relief, said two frontal regions meet in said intermediate region by forming, for each relief, n (n being an integer equal to or greater than 3) discontinuous convex bulges which are substantially in the form of a circular arc in the circumferential and axial directions in said intermediate region,
• wherein the respective contours of said reliefs are identical and angularly offset from one relief to another, the contour of each relief substantially defining a convex regular polygon with n sides and with n truncated summits respectively formed by said rounded sections, the reliefs following one another in alternation according to one and the same angular offset (α) of π/n radians by defining two angular positions for the polygons of all of these reliefs, and
• wherein, viewed in a longitudinal axial section of said at least one corrugated bendable portion, two said consecutive bulges are separated from one another in the axial direction by a substantially flat hollow defined by one of said at least three straight sections of an intermediate said relief located axially between said consecutive bulges.