Variable-pitch vane made of composite material for an unducted fan of an aircraft
A variable-pitch vane made of a composite material for an unducted fan of an aircraft, the vane including a fibrous reinforcement formed as a single piece of three-dimensional fabric obtained by three-dimensional weaving including an airfoil portion and a root portion forming a retaining bulb and intended to be connected to a variable-pitch mechanism, the three-dimensional weaving being carried out continuously between the root portion and the airfoil portion, the fibrous reinforcement defining an internal shaping cavity formed by a separation extending inside the root portion and the blade portion, wherein a matrix densifies the fibrous reinforcement and reinforcing metal shells are arranged around the root portion.
1 . A variable-pitch blade made of composite material for an unducted fan of an aircraft, comprising:
a fibrous reinforcement, formed as a single piece of three-dimensional fabric obtained by three-dimensional weaving, comprising an airfoil portion, and a root portion forming a retaining bulb and intended to be connected to a variable pitch mechanism, the three-dimensional weaving being accomplished continuously between the root portion and the airfoil portion, the fibrous reinforcement defining an internal shaping cavity, formed by a non-interlinking extending inside the root portion and the airfoil portion,
a matrix densifying said fibrous reinforcement, and
metal reinforcing shells applied around the root portion.
2 . The variable-pitch blade according to claim 1 , wherein the airfoil portion defines two second internal shaping cavities, formed by a second non-interlinking leading to the root portion and located on either side of the shaping cavity, the metal reinforcing shells being partly accommodated in the second shaping cavities.
3 . The variable-pitch blade according to claim 2 , wherein a larger transverse dimension, defined between the metal reinforcing shells, measured in a chord direction, is substantially constant in the second shaping cavities.
4 . The variable-pitch blade according to claim 2 , wherein a shaping element made of cellular or porous material, distinct from the metal reinforcing shells, is present in each of the second shaping cavities.
5 . The variable-pitch blade according to claim 2 , wherein the airfoil portion comprises, in a segment of its longitudinal dimension adjacent to the root portion, a main woven portion defining a leading edge and a trailing edge, said main woven portion being separated at the second non-interlinking into skin woven portions each delimiting a respective second shaping cavity, and an intermediate woven portion located between the skin woven portions, said intermediate portion being separated at the non-interlinking into two separated portions delimiting the shaping cavity.
6 . The variable-pitch blade according to claim 1 , wherein the blade also comprises a shaping part present in the internal shaping cavity, said shaping part being hollow at least at a lower longitudinal end of the blade.
7 . The variable-pitch blade according to claim 1 , wherein the root portion comprises a mounting portion defining the retaining bulb, and a stilt portion which provides a transition between the mounting portion and the airfoil portion, the metal reinforcing shells extending around the mounting and stilt portions.
8 . The variable-pitch blade according to claim 1 , wherein the fibrous reinforcement is formed from carbon fibers, from glass fibers, from aramid fibers, or from a mixture of such fibers.
9 . The variable-pitch blade according to claim 1 , wherein the matrix is an epoxy resin.
10 . An unducted fan intended to be mounted on an aircraft, comprising a hub comprising blade attachment portions, and a plurality of variable-pitch blades, each variable-pitch blade being according to claim 1 , mounted on the blade attachment portions.