FR3139493A1 - FIBROUS TEXTURE OF BLADE OR PROPELLER FOOT - Google Patents

Abstract

FIBROUS TEXTURE OF A BLADE OR PROPELLER STOT The present invention relates to a fibrous texture (1) comprising at least one portion (3) of the root forming a fibrous reinforcement of the dovetail blade or propeller root and produced by three-dimensional weaving in a single piece, the foot portion comprising an intrados surface (3a) and an extrados surface (3b) each having a textile portion (5a; 5b) for radially blocking the foot forming a local extra thickness. Figure for abstract: Fig. 1.

Description

FIBROUS TEXTURE OF BLADE OR PROPELLER FOOT

The present invention relates to a fibrous texture intended to form the fibrous reinforcement of a blade or propeller made of composite material, comprising a foot portion incorporating textile portions for radially blocking the foot which are capable of coming into contact with a disc positioning to retain the blade or propeller on the disc. The invention also relates to associated composite material blades or propellers.

The fan blades of aeronautical turbomachines are commonly made of organic matrix composite (OMC) material. CMOs withstand temperatures ranging from 100°C to 250°C. These materials replace parts made of metallic material. Their use contributes to optimizing the performance of turbomachines or turbomachine equipment, in particular by reducing the overall mass of the turbomachine, thus reducing fuel consumption which in turn leads to a reduction in harmful emissions (CO, CO ₂ , NO _x …).

The fan blades are positioned on a rotating disk which includes a plurality of cells in which the blade roots are intended to be housed. It is known to position a wear material on the intrados and extrados surfaces of the composite blade roots which is intended to come into contact with the positioning disk, in particular with a foil mounted on the latter, to ensure radial blocking of the feet in the alveoli. This wear material is a material distinct from the composite material forming the blade root and requires separate manufacturing or specific supply as well as a step of securing to the composite root. This results in an extension of the manufacturing range. It is desirable to simplify obtaining these radial blocking portions.

The present invention relates to a fibrous texture comprising at least one foot portion forming a fibrous reinforcement of the blade root or dovetail propeller and produced by three-dimensional weaving in a single piece, the foot portion comprising an intrados surface and an extrados surface each having a textile portion for radially blocking the foot forming a local extra thickness.

The textile radial locking portions of the foot are integrated into the texture and make it possible to dispense with the added wear material, thus simplifying obtaining the interface zone with the positioning disc. In addition, the fact that the blocking portions are co-woven with the rest of the foot portion makes it possible to improve their mechanical strength compared to the prior technique.

In an exemplary embodiment, each textile radial blocking portion of the foot is located at a non-zero distance from an upstream axial end of the foot portion.

Such a characteristic advantageously makes it possible to ensure contact with the positioning disk elsewhere than on the upstream axial end which already constitutes a significant area of application of forces and thus to unload this area.

In an exemplary embodiment, the foot portion comprises a core region located between the intrados and extrados surfaces, at least part of the threads present in each radial blocking textile portion having a density greater than the density of the threads in the core region .

Such a characteristic advantageously makes it possible to improve the wear resistance of the blade or propeller root in operation.

In an exemplary embodiment, the local extra thickness defined by each radial blocking textile portion is between 1 mm and 5 mm.

Such a characteristic advantageously allows for slowed wear kinetics.

In an exemplary embodiment, an axial dimension of each radial blocking textile portion is between 2/3 and 3/4 of an axial dimension of the foot portion.

In an exemplary embodiment, the fibrous texture forms a fibrous blade or propeller preform, further comprising a blade portion co-woven or attached to the root portion.

The invention relates to a turbomachine blade comprising a fibrous texture as described above, and an organic matrix densifying it. The blade is, for example, an aeronautical fan blade.

Alternatively, the invention relates to a helix comprising a fibrous texture as described above and an organic matrix densifying it.

The invention also relates to a turbomachine wheel comprising a positioning disk comprising a plurality of cells in which several blades or propellers are positioned as described above.

There represents, schematically and partially, an example of fibrous texture according to the invention forming a fibrous fan blade preform.

There represents, schematically and partially, a detail of the fibrous texture of the at the level of the foot portion.

There is a sectional view along III-III showing an example of a weaving weave plan in the foot portion.

There represents, schematically and partially, blades according to the invention mounted on a positioning disk.

The invention will, in the following, be described in connection with an application to an aeronautical turbomachine blade but the details below remain applicable to a propeller intended to be mounted in an aircraft.

We represented at the an example of fibrous texture 1 which comprises a foot portion 3 which is woven in a single piece with a blade portion 20 by three-dimensional weaving. The illustrated example concerns a case where there is textile continuity between portion 3 and portion 20. However, we do not depart from the scope of the invention when the fibrous texture comprises a foot portion which is attached to a portion of hollow blade. In this case, the root portion may comprise, at an external radial end, a projecting element capable of being introduced into an interior volume of the blade portion in order to position the latter on the root portion.

Texture 1 is obtained by three-dimensional weaving of first and second threads and forms, in the example illustrated, a single piece of fabric. By “three-dimensional weaving” or “3D weaving”, we mean here a mode of weaving by which at least some of the first threads bind second threads on several layers of second threads. The first threads may be warp threads and the second threads may be weft threads or, conversely, the first threads may be weft threads and the second threads may be warp threads. The warp threads can extend along the radial direction DR and the weft threads along the axial direction DA. Unless otherwise stated, a reversal of roles between warp and weft is possible in the following text, and must be considered as also covered by the claims. The radial DR direction corresponds to the direction according to the height of the blade or propeller, connecting its root to its top. The axial DA direction corresponds to the direction along the chord of the blade or propeller as well as the direction of air flow in operation. Generally speaking, texture 1 may include carbon threads, glass threads, or a mixture of such threads.

In the example of the , the texture 1 is in the shape of the blade to be obtained by giving in particular to the portion 20 the shape of the desired aerodynamic profile. For this, the texture is shaped in a shaper in a manner known per se before proceeding with the introduction of a matrix material which makes it possible to obtain the part in composite material and to freeze it at the desired shape.

Portion 3 forms the fibrous reinforcement of a dovetail blade root to be obtained. Portion 3 has in particular the shape of the blade root to be obtained. Portion 3 is obtained by three-dimensional weaving of the first and second threads and forms a single piece of fabric. The portion 3 comprises an intrados surface 3a which is located on the side of the intrados 20a of the portion 20, and an extrados surface 3b which is located on the side of the extrados 20b of the portion 20. In the case of a portion of the blade portion, the intrados surface of the root portion corresponds to the surface intended to be located on the intrados side of the blade portion once it has been attached, and the extrados surface of the root portion corresponds to the surface intended to be located on the upper surface side of the blade portion once it has been attached. Portion 3 here is dovetailed and surfaces 3a, 3b have an inclined shape with a non-zero angle relative to the radial direction DR in a plane normal to the axial direction DA. Each of the surfaces 3a, 3b has a textile portion 5a, 5b for radially blocking the foot which forms a local extra thickness, as visible on the . Portions 5a, 5b are configured to ensure radial locking of the blade root when it is mounted in a cell AL of a positioning disk D (see ). Portions 5a, 5b can have the same shape and the same dimensions. Portion 3 comprises a core region 4 which is located between portions 5a, 5b. Portions 5a, 4 and 5b are offset along the circumferential DC direction of texture 1. The circumferential DC direction corresponds to the direction along the circumference of the positioning disk, around the axis of the latter. Portions 5a, 5b are co-woven with region 4. These portions 5a, 5b can be produced by three-dimensional weaving of first and second threads, with part of the first threads of these portions 5a, 5b linking layers of second threads of region 4, as shown in Figure which will be described below. However, we do not depart from the scope of the invention when the portions 5a, 5b do not correspond to woven portions, we can in fact produce an exit of threads from region 4 to locally form unidirectional fibrous portions defining the blocking portion of the foot in excess thickness.

Figures 2 and 3 which will now be described provide more details on portion 3 and portions 5a, 5b. This example concerns the case of portions 5a, 5b produced by three-dimensional weaving but those skilled in the art will recognize that this teaching applies mutatis mutandis to portions 5a, 5b formed by unidirectional fibrous layers.

There illustrates a front view of surface 3a, it being understood that a similar arrangement applies to surface 3b and portion 5b. Portion 5a can form a connected textile portion (in one piece), as illustrated. It can have a substantially polygonal shape, for example rectangular in the case illustrated, in a plane normal to the circumferential DC direction. Portion 5a may have an elongated shape along the axial direction DA. Portion 5a can be spaced from the upstream axial ends EA1 and downstream EA2 of portion 3 by a non-zero distance, denoted A7a and A9a. The terms “upstream” and “downstream” are used here in reference to the direction of air flow around the blade or propeller. Thus, the surface 3a is defined, along the axial direction DA, by a portion 7a, the portion 5a which, like a step, produces a local extra thickness, and a portion 9a. Portion 5a forms a projecting relief. As illustrated, we can have a portion 5a which is centered along the axial dimension A3 of the portion 3, the distances A7a and A9a thus being substantially equal. In the example of the , the axial dimension A5a of portion 5a is between 2/3 and 3/4 of the axial dimension A3 of portion 3. In which case, each of the distances A7a and A9a may be greater than or equal to 1/8 of dimension A3, and for example be between 1/8 and 1/6 of dimension A3.

Portions 5a, 5b are obtained by locally adding additional layers of first wires 6a, 6b and second wires 8a, 8b compared to the initial definition of the blade which here corresponds to core region 4 obtained by weaving first 6 and second 8 threads. A local extra thickness e5a, e5b, defined by each portion 5a, 5b, greater than or equal to 1 mm, for example between 1 mm and 5 mm, is thus obtained on the surfaces 3a, 3b. Portions 5a, 5b and a core region 4 are shown, each co-woven with an “interlock” weave in which each layer of first threads links several layers of second threads with all the threads of the same column of first threads. having the same movement in the plane of the armor. Those skilled in the art will recognize that other weaving weaves are possible without departing from the scope of the invention. As visible at , extra lengths of first 6a and second 8a wires are obtained after weaving of the portion 5a which are then cut, before the introduction of the matrix material. Portions 5a, 5b are co-woven with core region 4 by the presence of threads 8at, 8bt which link layers of threads from portions 5a, 5b with layers of threads from core region 4. Furthermore, in the example illustrated, the portions 5a, 5b have threads 6a, 6b having a density greater than the density of the threads 6 in region 4. The threads 6a, 6b can have a density greater than or equal to 24k, for example example between 24k and 72k.

The composite material part is then obtained, from texture 1 put into the desired shape, by introducing a matrix material into the porosity of this texture 1 so as to densify it. It is thus possible to obtain an organic matrix composite by introducing a resin into the porosity of texture 1 by implementing techniques known per se. The resin can be thermoplastic or thermosetting, in the latter case the introduction of the resin can be followed by a crosslinking heat treatment so as to obtain the composite material. The resin introduced can for example be an epoxy resin.

We represented at the the positioning of a plurality of blades 11 made of composite material in the cells AL of a positioning disk D. These may for example be fan blades. The blades 11 have the same shape as the texture 1 previously described with a blade portion 201 which has an intrados 201a and an extrados 201b, as well as a root portion 31 which comprises radial locking portions 51a, 51b which come into contact with each other. support with the positioning disk D and possibly with a CL foil attached to it, as illustrated. In this way, the blades 11 are retained radially in the cells AL. A core region 41 is located between portions 51a, 51b. In the example illustrated, a wedge C is present at an internal radial end of the foot portion 31.

The expression “between… and…” must be understood as including the limits.

Claims (10)

Fibrous texture (1) comprising at least one root portion (3) forming a fibrous reinforcement of the blade root or dovetail propeller and produced by three-dimensional weaving in a single piece, the root portion comprising a surface (3a) intrados and an extrados surface (3b) each having a textile portion (5a; 5b) for radial blocking of the foot forming a local extra thickness. Fibrous texture (1) according to claim 1, in which each textile portion (5a; 5b) for radially blocking the foot is located at a non-zero distance (A7a) from an axial end (EA1) upstream of the portion (3) of foot. Fibrous texture (1) according to claim 1 or 2, in which the foot portion (3) comprises a core region (4) located between the intrados (3a) and extrados (3b) surfaces, at least part of the threads present in each textile portion (5a; 5b) of radial blocking having a title greater than the title of the threads in the core region. Fibrous texture (1) according to any one of claims 1 to 3, in which the local extra thickness (e5a; e5b) defined by each radial blocking textile portion (5a; 5b) is between 1 mm and 5 mm. Fibrous texture (1) according to any one of claims 1 to 4, in which an axial dimension (A5a) of each radial blocking textile portion (5a; 5b) is between 2/3 and 3/4 of an axial dimension (A3) of the foot portion (3). Fibrous texture (1) according to any one of claims 1 to 5, forming a fibrous blade or propeller preform, further comprising a portion (20) of blade co-woven or attached to the portion (3) of foot. Turbomachine blade (11) comprising a fibrous texture (1) according to claim 6, and an organic matrix densifying it. Turbomachine blade (11) according to claim 7, in which the blade is an aeronautical fan blade. Helix comprising a fibrous texture according to claim 6, and an organic matrix densifying it. Turbomachine wheel comprising a positioning disk (D) comprising a plurality of cells (AL) in which several blades (11) or propellers according to any one of claims 7 to 9 are positioned.