Blade-hub linkage device with a laminate attachment

A blade-hub linkage device incorporating a blade to be fastened to a rotor hub, said blade comprising:

• a rigid shell, with aerodynamic profile, elongated longitudinally along the span of the blade, and having a tubular blade root on the side attached to the hub,
• a strengthened framework which is at least partially housed substantially longitudinally in the shell, and
• a blade rooting part, comprising at least one elongated torsion bar for attachment of the blade, said torsion bar being twistable about its longitudinal axis, made from composite material and comprised of substantially unidirectional fibers agglomerated by a rigidified synthetic resin, said torsion bar being linked to said framework and extending at least partially outside the shell and passing through the blade root, said blade-hub linkage device comprising, for said at least one torsion bar of the rooting part, a laminate attachment including at least two laminate elements between which a bar end portion for linking said torsion bar to the hub is sandwiched and fixed, said end portion being situated along the longitudinal axis of the shell and being substantially flattened, each laminate element comprising a stack of at least two layers of fibers which are agglomerated by a rigidified synthetic resin, at least one of the resins of the bar and of the laminate attachment solidly joining said laminate elements to said end portion, the solid combination of said laminate attachment and the end portion of said bar being in abutment against means for holding the laminate attachment and the blade to the hub.

A multiblade rotor comprising:

• a drive shaft for being driven in rotation about an axis of rotation of the rotor,
• a hub linked in rotation with the drive shaft,
• a plurality of blades, each of which is joined to the hub by a rooting part with at least one composite, elongate torsion bar, wherein each blade comprises
• a rigid shell, with aerodynamic profile, elongated longitudinally along the span of the blade, and having a tubular blade root on the side attached to the hub, and
• a strengthened framework, which is at least partially housed substantially longitudinally in the shell, said at least one torsion bar being twistable about its longitudinal axis, made from composite material and comprised of substantially unidirectional fibers agglomerated by a rigidified synthetic resin, said at least one torsion bar being linked to said framework and extending at least partially outside the shell and passing through the blade root, the rooting part of each said blade being joined to the hub by a blade-hub linkage device which comprises for said at least one bar of the rooting part, a laminate attachment including at least two laminate elements between which a bar end portion for linking said bar to the hub is sandwiched and fixed, said end portion being substantially flattened, each laminate element comprising a stack of at least two layers of fibers which are agglomerated by a rigidified synthetic resin, at least one of the resins of the bar and of the laminate attachment solidly joining said laminate elements to said end portion, the solid combination of said laminate attachment and the end portion of said bar being in abutment against means for holding the laminate attachment and the blade to the hub.