Blade made of organic matrix composite material provided with a metal strip, and a method of fastening a metal strip on a blade fiber preform

Patent metadata

Field	Value
Publication number	US-10240463-B2
Application number	US-201615070585-A
Country	US
Kind code	B2
Filing date	Mar 15, 2016
Priority date	Mar 16, 2015
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A blade made of organic matrix composite material for a gas turbine aeroengine, includes an airfoil extending transversely between a leading edge and a trailing edge; and a metal strip positioned on the leading edge of the airfoil, the metal strip having two flanges extending on either side of the leading edge over portions of the side faces of the airfoil forming a pressure side face and a suction side face so that the strip fits closely to the profile of the leading edge, the metal strip being fastened to the leading edge of the airfoil by at least one stitching thread; wherein the stitching thread has at least one external thread segment extending substantially transversely between a hole formed through a flange of the strip and a passage formed in a portion of the airfoil that has at least one face that is not covered by the metal strip.

First claim

The invention claimed is:

1. A blade made of organic matrix composite material for a gas turbine aeroengine, the blade comprising:
an airfoil extending transversely between a leading edge and a trailing edge; and
a metal strip positioned on the leading edge of the airfoil, said metal strip having two flanges extending on either side of the leading edge over portions of side faces of the airfoil forming a pressure side face and a suction side face in such a manner that the metal strip fits closely to the profile of the leading edge, the metal strip being fastened to the leading edge of the airfoil by at least one stitching thread;
wherein said stitching thread has at least one external thread segment extending substantially along a transverse direction of the blade between a hole formed through a flange of the metal strip and a passage formed in a portion of the airfoil that has a surface that is not covered by the metal strip, said transverse direction connecting the leading edge and the trailing edge of the blade.

2. A blade according to claim 1 , wherein the two flanges of the metal strip are connected together by the at least one stitching thread.

3. A blade according to claim 2 , wherein the at least one stitching thread connecting together the two flanges of the metal strip comprises at least one stitching loop that comprises:
a first internal thread segment passing through the airfoil across its thickness from its suction side face to its pressure side face via the passage through the airfoil;
a first external thread segment extending from a free end of the first internal thread segment substantially along the transverse direction of the blade and beside the pressure side face of the airfoil;
a second internal thread segment extending from a free end of the first external thread segment and passing through the airfoil across its thickness from its pressure side face to its suction side face;
a second external thread segment extending from the free end of the second internal thread segment substantially along the transverse direction of the blade and beside the suction side face of the airfoil towards the first internal thread segment; and
a third internal thread segment passing through the airfoil across its thickness from its suction side face towards its pressure side face along the same path as the first internal thread segment.

4. A blade according to claim 3 , comprising a plurality of stitching loops and/or double stitching loops that are longitudinally spaced apart from one another along the height of the airfoil.

5. A blade according to claim 3 , wherein a single stitching thread passes at least twice around a stitching loop or a double stitching loop.

6. A blade according to claim 2 , wherein the at least one stitching thread connecting together the two flanges of the metal strip includes at least one double stitching loop that comprises:
a first internal thread segment passing through the airfoil across its thickness from its suction side face to its pressure side face via the passage in the airfoil;
a first external thread segment extending from a free end of the first internal thread segment substantially along the transverse direction of the blade and beside the pressure side face of the airfoil;
a second internal thread segment extending from a free end of the first external thread segment and passing through the airfoil across its thickness from its pressure side face to its suction side face;
a second external thread segment extending from a free end of the second internal thread segment substantially along the transverse direction of the blade and beside the suction side face of the airfoil away from the first internal thread segment;
a third internal thread segment extending from a free end of the second external thread segment through the airfoil across its thickness from its suction side face to its pressure side face;
a third external thread segment extending from a free end of the third internal thread segment substantially along the transverse direction of the blade and beside the pressure side face of the airfoil towards the second internal thread segment;
a fourth internal thread segment extending from a free end of the third external thread segment and passing through the airfoil along the path of the second internal thread segment;
a fourth external thread segment extending from a free end of the fourth internal thread segment substantially along the transverse direction of the blade and beside the suction side face of the airfoil towards the first internal thread segment; and
a fifth internal thread segment extending from a free end of the fourth external thread segment and through the airfoil following the path of the first internal thread segment.

7. A turbine engine comprising a blade according to claim 1 .

8. A method of fastening a metal strip on a fiber preform for a gas turbine aeroengine blade, the method comprising:
positioning the metal strip on a leading edge of the fiber preform of the blade; and
fastening the metal strip on the fiber preform of the blade, the fastening comprising forming at least one stitching loop with at least one stitching thread, said least one stitching thread comprising at least one external thread segment extending substantially along a transverse direction of the blade between a hole formed through a flange of the strip and a passage formed in a portion of the fiber preform that has a surface that is not covered by the metal strip, said transverse direction connecting the leading edge and a trailing edge of the blade.

9. A method according to claim 8 , wherein, in order to form a stitching loop, the least one stitching thread passes initially through the airfoil from its suction side face to its pressure side face via the passage in the preform so as to form a first internal thread segment, said least one stitching thread then passes through the preform across its thickness from its pressure side face to its suction side face passing via the holes formed in each of the flanges of the strip so as to form a second internal thread segment, the first internal thread segment and the second internal thread segment being connected together by a first external thread segment that extends along the transverse direction, said least one stitching thread finally passes through the preform across its thickness following the path of the first internal thread segment so as to form a third internal thread segment, the second internal thread segment and the third internal thread segment being connected together by a second external thread segment that extends along the transverse direction.

10. A method according to claim 8 , further comprising injecting a thermoactive or thermoplastic resin into injection tooling having placed therein the fiber preform of the blade with the metal strip fastened thereon so as to embed the least one stitching thread in the resin and overmold the metal strip.

11. A turbine engine comprising a metal strip fastened on a blade fiber preform by a method according to claim 8 .

Assignees

• Snecma
• Safran Aircraft Engines

Inventors

• Notarianni Gilles Pierre-Marie
• Gimat Matthieu Arnaud
• Guivarc'H Jérémy
• Ruf Thibault

Classifications

• B29C70/48

  and impregnating the reinforcements in the closed mould, e.g. resin transfer moulding [RTM] {, e.g. by vacuum} · CPC title

• F05D2300/10

  Metals, alloys or intermetallic compounds · CPC title

• F05D2220/32

  in gas turbines · CPC title

• F01D5/147 Primary

  Construction, i.e. structural features, e.g. of weight-saving hollow blades (F01D5/148, F01D5/16 and F01D5/20 take precedence; blade shape F01D5/141; blades with cooling or heating channels or cavities F01D5/18; heating, heat-insulating or cooling means on blades F01D5/18) · CPC title

• F05D2220/36

  specially adapted for the fan of turbofan engines · CPC title