RTM injection method and mould using symmetric anti-pinching sectors

A method of closing an injection mold for the manufacture of an axisymmetric part of composite material, the mold comprising:

• a mandrel supporting a fibrous preform obtained by winding a fibrous strip, the mandrel comprising an annular wall having an outer surface and an inner surface, a profile of the outer surface corresponding to a profile of the inner surface of the part to be manufactured,
• a plurality of angular sectors comprising an annular base intended to come into contact with the fibrous preform, the annular base extending between first and second longitudinal edges in an axial direction and between first and second lateral edges in a circumferential direction,
• wherein the plurality of angular sectors each comprises a first series of angular sectors and a second series of angular sectors, the first and second lateral edges of each angular sector of the first series of sectors each including a protruding lower portion forming a first nonzero angle relative to a radial direction, the first and second lateral edges of each angular sector of the second series of sectors each including a recessed lower portion forming a second nonzero angle relative to a radial direction, wherein the plurality of angular sectors further includes a first lateral face parallel to the radial direction and present in the continuation of the first lateral edge of each angular sector, and a second lateral face parallel to the radial direction and present in the continuation of the second lateral edge of each angular sector,
• the first angle and the second angle having the same extent and wherein the method comprises successive positioning and attachment of each angular sector on the mandrel,
• the annular base of each sector compacting the fibrous preform portion facing the annular base, the lateral edges of the annular base of an angular sector of the first series of sectors during positioning being held in contact with the lateral edges of the annular base of the angular sectors of the second series of sectors already attached to the mandrel.