FR2718101A1 - Blade according to a fiber-based composite manufacturing method having a protective profile in case of encountering foreign bodies, ice blocks, birds or others. - Google Patents

Abstract

a) Blade according to a composite manufacturing method having a protective profile in the event of encountering foreign bodies, blocks of ice, birds or the like, b) characterized in that the protective profile (5) is sewn by means of one or several threads (9) to be fixed on the blade (4) with the latter, the threads (9) passing transversely through a number of layers of fibers (12).

Description

"Pale according to a composite manufacturing method to

  fiber base having a protective profile in the event of

  The invention relates to a propeller or blower blade for turbomachines with a blade made according to the fiber-based composite construction method and with a protection profile arranged along the length of the blade. of the leading edge and / or the trailing edge of the blade, made separately from the fiber-based composite, in which blade the protective profile which extends in an enveloping manner, at least in sections on the pressure side and / or in aspiration of

  the blade with respect to a median line of the blade.

  Because of their favorable properties in the

  in the field of materials technology, we manufacture

  turbomachines, such as blower blades

  turbine engines, propeller blades and rotor blades of helicopters and wind turbines increasingly made of material reinforced with fibers. These materials have the advantage of having a high strength and a low weight, moreover they have their own disadvantage of being sensitive to erosion in operation. They are subject according to their conditions of use to rain and erosion by particles (for example insects and sand). In particular, they react sensitively when they encounter large enough foreign objects, such as for example blocks of ice, stones,

  birds among others. This disadvantage is particularly

  for the narrow leading edges of the blades, and especially as the relative speed of the blade is high.

  compared to that of the particle colliding.

  However, there is no reason to tolerate a modification of the profile due to erosion with regard to the preservation of high aerodynamic quality. To protect rotor blades, it is known in the field of helicopter construction to provide the leading edge of the blade of a glued sheet metal profile. It did appear, however, that

  where vibrating shots are applied, for example

  due to foreign bodies, that the location of the bonding is faulty and that the sheet metal profile then flakes more often and is completely detached from the rest of the

blade.

  On the basis of this, the object of the invention is to

  to provide protection against erosion and body impact

  foreigners for propeller blades and blower blades.

  in the modes of construction employing

  fiber-based sites, protection that also forms in case

  local damage a reliable connection with the blade.

  According to the invention, the problem is solved by virtue of the fact that the protection profile is sewn by means of a

  or several wires by reinforcement on the blade with that

  ci, the wires passing transversely across a certain

number of layers of fibers.

  The device according to the invention has the advantage

  that by sewing the protection profile on the blade, we ob-

  The bond between the latter forms a bond which greatly increases the adhesion of the protection profile to the blade, in particular after the sudden impact of a foreign body on the protection profile with respect to a bonding bond. An essential advantage lies in the

  even if there is destruction or damage

  seams, that is to say, in the case where threads are torn off, the seam does not continue to unravel on the damaged area, because the threads that were passed through

  through layers of fibers form because of their adherence

  A strong connection to the fiber layers is achieved and in this way the seam is securely prevented from snagging. According to a preferred development of the invention, the protection profile is formed in the area of the leading edges or the trailing edges of the blades with a contour having the shape of a U or a V. In this way, reliable protection even in the case of foreign bodies

arriving across.

  According to other characteristics of the invention: the protection profile has bores which extend perpendicular to the surface of the blade, bores through which threads (9) are passed to sew them with the blade; - The holes are provided on the pressure side and the suction side on the protection profile; the bores are provided upside down from the leading or trailing edges of the blade in the edge region of the protection profile; the protection profile has protrusions extending from the pressure side and / or the suction side with respect to a median line of the blade (M), located at a

  certain distance from each other in the long-term

  dinal of the blade, projections which are provided with holes for sewing with the blade; - the extension of the projections in the depth of

  the blade and in the length of the blade as well as their

  from each other are determined in such a way as to

  dampen the vibrations of the propeller blade or

  flante; - The holes have on the flow side a cavity for receiving flat on the surface son;

  - in the protection profile, it is possible to

  be the holes on the flow side of the recesses which serve to receive the son extending on the side of the flow elongated way; the threads are knotted on the flow side to be fixed in places in the bores; the wires are placed in the bores on the flow side in knots and are fixed by means of transverse threads passing through the knots; - the blade is sewn in the shape of a zigzag between the

  branches of the protection profile which extend

  port in the middle (M) of the blade on the suction side and on the pressure side; the wires extend in the depth of the blade and / or in the length of the blade by zigzag-sewing a number of layers of fibers; - The protection profile has cleats that engage in the fiber layers by an additional connection by shape with the blade; - To ensure additional attachment of the protection profile on the blade, it is glued with the protection profile; - the protection profile is filled to ensure additional fixation on the flow side, at

  less in part, of a fiber-based composite layer.

  To avoid the formation on the surface of the blade of steps generating resistance, cavities are provided in the holes and recesses between the

  holes used to receive the wires flat on the surface.

  face. Because of the obvious position of cavities and

  indentations on the surface of the profile the joints of

  are accessible without having any other expenditure on

  visual inspection for the purpose of

  wires that are detached indicate a damaged seam.

  Preferably, the protection profile is

  seen from inward-facing studs, which amplify the interpenetration bond by the shape between the blade and

  the protection profile, by taking in the layers of

  fibers. The present invention will be described hereinafter

  in more detail using alternative embodiments of

  shown in the accompanying drawings in which: - Figure 1 shows a view of a turboprop blade with protection profiles; FIG. 2 represents a cross section of the turboprop blade according to FIG. 1; - Figure 3 shows an enlarged fragment of the turboprop blade in the area of a sewn hole, according to Figure 2; FIG. 4 shows an enlarged fragment of the turboprop blade in the area of a wire knotted in the

drilling, according to Figure 2.

  - Figure 5 shows a partial view in pers-

  pective in the area of the leading edge of the blade with a protection profile; and - Figure 6 shows a diagram serving a

  Peel test of a FVK-2D and 3D blade sample.

  In the case of the fan blade 1 represents

  In FIG. 1, a turbo-prop engine has not been shown, the leading edge 2 and the trailing edge 3 of the blade 4 are provided with protective metal sections 5 for protect the blade from erosion and the impact of foreign bodies, shaped

  extend from the tip of the blade 6 to almost

  In order to reinforce the connection by gluing between the blade 4 and the protection profiles 5, they are sewn respectively along their profiled edge 8 turned towards the median line of the blade M with the blade 4

  in several sections. The threads 9 of the seams 10 extend

  tooth in this case in a straight line in sections, curved or serrated along the edge of the profile 8 or also intersecting with son 9 'of another seam 10' over the width of the

  5. The seams 10 can therefore

  They may extend in different models each depending on the width and length of the protection profile 5 and the requirements of the connection. To join by sewing the blade 4 manufactured according to the composite fiber-based construction and the protection profile 5, it is provided with holes 11, through which the threads are passed 9. As can be seen more in detail in cross-section in FIG. 2, the threads 9 of the seams 10 'which extend in the direction of the depth of the blade pass through the layers of fibers 12 of blade 4, making

  zigzag, layers that extend in the direction of the long

  and the depth of the blade. To prevent the

  In order to cut through, the end of the fiber 13 'is laminated between two fiber layers 12', while an alternative fastener is sewn on another end of the fiber.

  13 "fiber to a 12" fiber layer. As additional fixation

  of the protection profile 5 on the blade 4 the edges of the profile 8 have hooks turned towards

  inside the blade, which come into contact with a certain

  number of layers of surface fibers 12.

  To mitigate the risk of basting, we use

  for a number of seams 10 being narrowly

  next to one another and extending in the transverse direction and in the longitudinal direction an uninterrupted individual wire 9 instead of several separate short wires 9, as shown in Figure 2 in the area of the edge of 2. For this, the wire 9 is intermingled at cross points seams 10 which extend in the longitudinal direction and in the transverse direction, as shown in Figure 3. At this point a piece of wire is placed inside a hole 11 in a closed hook 15, and a piece of transversely extending wire is twisted therein. It is knotted in a superficial cavity 16 of the bore 11 (see Figure 4) and in this way it prevents loosening of the son 9 which ends

  superficially in drilling.

  application of the seams 10 which extend superficially, provision is made between the holes 11 on the surface of the protection profile 5 groove-type recesses 17, of which

  the depth is adjusted to the thickness of a wire 9 to receive

see this one (see Figure 5).

  To avoid a vibration of the blade 1 to vi-

  specified rotational speeds or to cushion them, the

  protection yarn 5 has a plurality of protruding protrusions 18 along the edge of the profile 8 in the region of the tip of the blade 6. The protrusions 18 are made to

  a certain distance from each other in the long-term

  gitudinal of the blade and sink towards the middle M of the blade. To have a secure connection, we sew

projections 18 to the blade 4.

  Figure 6 shows in a diagram the increased impact resistance of a fiber-based composite bond

  sewn in relation to a composite bond based on

  which is not sewn. To simulate the action of a wave

  shock triggered by the vertical impact of a foreign body

  However, the ends of the fiber samples were removed by peeling. As can be seen in the diagram, it is necessary to peel the stitched sample of fiber-based composite to have a shape F about ten times larger, which shows that there is increased resistance of the blade 1 than previously described with respect to the impact of a foreign body and corrosion. The serrations in the bend make significant the influence of sewing on

the forcing of solidity.

R E V E N D I CATIONS

  1) Propeller blade or blower for turboma-

  with a blade made according to the composite fiber-based construction method and with a protection profile arranged along the leading edge and / or the trailing edge of

  the blade, made separately from the composite based on

  in which the protective profile which extends in an enveloping manner, at least in sections on the pressure side and / or in suction of the blade with respect to a median line of the blade, characterized in that the

  protection profile (5) is sewn by means of one or more

  sieurs son (9) by reinforcement on the blade (4) with it, the son (9) passing transversely through

  a number of layers of fibers (12).

  2) Blade or fan blade according to the

  1, characterized in that the protection profile

  tion (5) is formed in the area of the leading or trailing edges of the blade (2 or 3) in the form of a U-shaped or V-shaped contour.

  3) Blade of propeller or blower according to the

  claim 1 or 2, characterized in that the profile of

  protection has bores (11) which extend

  pendicular to the surface of the blade, piercing through

  to which threads (9) are passed for sewing

with the blade (4).

  4) Blade of propeller or blower according to the

  claim 3, characterized in that the bores (11) are provided on the pressure side and the suction side on the

protection profile (5).

   Blade or fan blade according to claim 3 or 4, characterized in that the bores (11) are provided upside down from the leading or trailing edges (2 or 3) of the blade in the border area of the profile of

protection (5).

  6) Propeller blade or blower according to one

  any of the preceding claims, characterized in that

  the protective profile (5) has protrusions extending from the pressure side and / or the side with respect to a center line of the blade (M), located at a distance from each other in the direction longitudinal section of the blade, projections which are provided with holes (11) for

sewing with the blade (4).

  7) Propeller blade or blower according to the

  O10 vendication 6, characterized in that the extension of the projections in the depth of the blade and in the length of the blade and their spacing from each other are determined so as to damp the vibrations of the blade.

propeller blade or blower.

  8) Propeller blade or blower according to one

  any of claims 3 to 7, characterized in that

  the bores (11) have on the flow side a cavity (16) for receiving flat on the surface the

son (9).

  9) Propeller blade or blower according to one

  any of claims 3 to 8, characterized in that

  in the protection profile (5), recesses (17) are formed between the bores (11) on the flow side which serve to receive the wires (9) extending from the side

  of elongated flow.

   ) Blade of propeller or blower according to one

  any of claims 3 to 9, characterized in that

  the threads (9) are knotted on the side of the flow to be

  fixed in places in the holes (11).

  11) Propeller blade or blower according to one

  any of claims 3 to 10, characterized in that

  the wires (9) are placed in the bores (11) on the flow side in knots (15) and are secured by means of

  transverse threads passing through the knots (15).

  12) Propeller blade or blower according to one

  any of the preceding claims, characterized in that

  that the blade (4) is sewn in the form of a zigzag between the branches of the protection profile (5) which extend with respect to the middle (M) of the blade on the suction side and the

pressure side.

  13) Propeller blade or blower according to one

  any of the preceding claims, characterized in that

  that the threads (9) extend in the depth of the blade and / or in the length of the blade by sewing in shape

  zigzag a number of layers of fibers (12).

  14) Propeller blade or blower according to one

  any of the preceding claims, characterized in that

  the protective profile (5) has crampons (14) which engage in the fiber layers by

  an additional connection by the shape with the blade (4).

   ) Blade of propeller or blower according to one

  any of the preceding claims, characterized in that

  in order to ensure additional fastening of the protection profile (5) on the blade (4), this is bonded with

the protection profile (5).

  16) Propeller blade or blower according to one

  any of the preceding claims, characterized in that

  the protective profile (5) is filled to provide additional flow-side attachment, at least in part, of a fiber-based composite layer (12).