Assembly comprising a wheel blade and a wheel blade pitch setting system

Abstract

The invention relates to an assembly for aeronautical turbine engines, comprising a unducted propeller blade (10) and a system (34) for setting the pitch of the blade (10), and also comprising: - a blade (10) whose root (14) has a bulb (32); - a system (34) for setting the pitch of the blade (10) about a pitch setting axis (A), the pitch setting system (34) comprising a cup (58) intended to be arranged inside a outer casing (73) and having a diverging open top for axial insertion of the root (14), and the root (14) of the blade (10) being axially fixed in the cup by a locking member (52); the assembly being characterized in that it further comprises at least one radial retention prong (77) in the radial space (E) reserved between the wall (58a) of the cup (58) and the root (14).

Description

Technical Field

[0001] This invention relates to the field of aircraft turbine engines, and particularly to propulsion propellers of such turbine engines that include variable-set blades. Background Technology

[0002] Prior art includes, in particular, documents FR-A1-3 017 163 and FR-A1-3 080 322.

[0003] The propeller of an aircraft turbine engine can be ducted (e.g., in the case of a fan) or unducted (e.g., in the case of an open rotor architecture).

[0004] A propeller includes blades, which can be variablely set. Therefore, a turbine engine includes a setting system that enables the blade setting angle to be changed so that the thrust generated by the propeller can be adapted to different stages of flight.

[0005] Propeller blade design involves multiple subjects with often conflicting objectives. Propeller blades must achieve optimal aerodynamic performance (i.e., providing thrust while maximizing efficiency), ensure mechanical strength (i.e., withstand mechanical stresses generated by static and dynamic loads), and limit mass and acoustic characteristics. In particular, improvements in propeller aerodynamic performance tend to increase the bypass ratio (BPR), which translates to increasing the propeller's outer diameter and thus the blade span.

[0006] In all existing attachment technologies, the blade root is mounted in a metal sleeve that engages with the rollers, allowing for variable configurations. These metal components are essential parts of the blade. In the event of blade loss, these metal components, with their high density compared to the composite materials constituting the rest of the blade, possess significant energy. However, since debris falling onto the ductless structure can impact the fuselage, the energy of the debris is a fundamental factor that needs to be optimized. Therefore, this is a factor to consider when determining the dimensions of the fuselage's protective components, especially the aircraft's mass.

[0007] The purpose of this invention is to reduce the risk of the fuselage being struck by components that could damage the fuselage, even if the device for attaching the blades to the mounting system malfunctions.

[0008] Another way to optimize aerodynamic performance is to improve efficiency near the hub by improving the quality of the aerodynamic flow. Controlling this flow is more complex because the blades typically have variable settings.

[0009] A variable-pitch blade propeller essentially comprises a hub that rotates about an axis of rotation and is equipped with housings for blades, the blades being pivotally mounted in these housings about a pitch setting axis that extends radially relative to the hub's axis of rotation. Each blade includes a root from which the blade extends. The root is mounted in a corresponding housing in the hub by bearings oriented along the radial axis, the bearings being inserted between an inner structural portion of the hub and the root of the blade to enable pivoting.

[0010] The hub typically includes a housing that forms the hub's aerodynamic fairing. Openings exist within this housing through which the receiving portion opens, and through which the roots of the impellers are inserted into the hub.

[0011] Therefore, at this fairing, near the opening, there are aerodynamic discontinuities, one on the one hand between the root of the blade and the edge of the opening, and the other on the other hand between the root of the blade and the blade itself. These aerodynamic discontinuities cause turbulence around the base of the blades, which degrades the overall aerodynamic efficiency of the propeller.

[0012] Among known technical solutions, a blade platform is provided that closes the orifice in the hub. This platform is designed to ensure good geometric continuity under specific settings and therefore at specific flight points. This point is typically chosen as the point where performance is optimized. When the settings change, the platform forms a stepped section through the hub. This damage to the geometry is a source of blade efficiency loss.

[0013] This platform is not a component that exists systematically in the existing ductless engine architecture.

[0014] Furthermore, when the platform exists, it serves as a fairing component to achieve aerodynamic performance and does not have structural functions. Summary of the Invention

[0015] This invention relates to a component for an aircraft turbine engine, the component including ductless propeller blades and a system for setting the blade pitch, the component comprising:

[0016] - The blade includes blades connected to a connecting root, the connecting root being intended to be attached to the hub of the propeller and to be received in a relevant opening in the outer casing of the hub, the root having a spherical section;

[0017] - A system for setting the pitch of a blade about a setting axis, the pitch setting system including a cup portion intended to be arranged within a housing, the cup portion including an open, tapering upper end portion for axially inserting a root portion into an annular wall of the cup portion, and the root portion of the blade being axially attached to the cup portion by a fixing member attached to the cup portion, the receiving cup portion being intended to be pivotally mounted relative to the hub about the setting axis;

[0018] The component is characterized in that it includes at least one retaining fork that extends radially from the wall of the cup to a radial space between the wall of the cup and the root, the fork being arranged axially opposite to the ball, and the fork being able to retain the root of the impeller within the cup by contacting the ball in the event of a failure of the component used to attach the root to the cup.

[0019] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the fork portion is integrally formed with the support member, which is assembled and attached to the cup portion.

[0020] In another aspect of the assembly manufactured in accordance with the teachings of the present invention, the support member includes an axially attached protrusion that abuts against the inner surface of the cup portion, and a fork portion extending radially from the axially attached protrusion.

[0021] In another aspect of the assembly manufactured in accordance with the teachings of the present invention, the support member includes a radial plate for attaching a platform intended to close an associated opening in the housing, the attachment plate being arranged at the upper end of the attachment protrusion and extending above the upper end edge of the cup portion.

[0022] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the fork may bend in the event of a failure of the component used to fix the root in the cup to axially suppress displacement of the root of the impeller.

[0023] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the fork has a main extension and an end extension, the main extension being radially inwardly oriented from the attachment protrusion, and the end extension being radially outwardly bent in the event of axial displacement of the root of the blade to facilitate deformation of the fork.

[0024] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the fork can be elastically bent and deformed at least a portion of the bending movement portion of the fork.

[0025] According to another aspect of the component manufactured in accordance with the teachings of the present invention, at the attachment position of the root of the impeller in the cup portion, the fork portion is arranged at an axial distance from the ball portion of the root.

[0026] According to another aspect of the component manufactured in accordance with the teachings of the present invention, at the attachment position of the root of the blade in the cup portion, the fork portion is arranged to be prestressed by bending against the ball portion of the root.

[0027] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the support member includes a plurality of forks evenly distributed around the root of the blade.

[0028] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the support member is made of a plurality of different sections, each of which is independently attached to the cup portion.

[0029] In another aspect of the component manufactured in accordance with the teachings of the present invention, the cup portion includes a shoulder surface that extends radially inward from the inner surface of the cup portion and axially upward supports a support member.

[0030] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the shoulder surface is formed by the lower surface of the edge, which extends radially inward from the upper end edge of the cup portion.

[0031] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the support member is radially outwardly supported against the inner surface of the cup portion.

[0032] According to another aspect of the assembly manufactured in accordance with the teachings of the present invention, the support member is attached to the cup portion by an attachment screw, the attachment screw being received in a through hole with a diameter larger than the diameter of the shank of the attachment screw, the screw being screwed into a nut and the screw being installed in the hole of the cup portion or in the hole of the attachment member having radial movement space, such that the axial force applied to the fork portion is transmitted upward only through the shoulder surface, and the attachment member abuts against the shoulder surface.

[0033] According to another aspect of the assembly manufactured in accordance with the teachings of the present invention, the fixing member is formed by a fixing ring extending about the axis and configured to be mounted around the root portion. The fixing ring is configured to be mounted inside the cup portion and to engage with the annular walls of the root portion and the cup portion respectively to ensure that the root portion is axially held in the cup portion.

[0034] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the fork portion extends axially opposite to the retaining ring.

[0035] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the retaining ring is a canine ring, which includes an outer canine portion configured to engage with an inner canine portion, the inner canine portion being complementary to the annular wall of the cup portion.

[0036] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the retaining ring has a wedge-shaped cross section and is configured to be axially biased outward from the cup portion under the action of centrifugal force during operation, and to keep the blade root axially fastened by the wedge effect.

[0037] According to another aspect of the component manufactured in accordance with the teachings of the present invention, the component further includes:

[0038] - A lower rolling guide bearing, which extends about the axis and is mounted around the lower portion of the annular wall.

[0039] - An upper rolling guide bearing extends about the axis and is mounted around the upper portion of the annular wall.

[0040] - At least one of the guide bearings has an inner ring that is integrated with the cup portion.

[0041] The present invention also relates to a turbine engine, specifically for use in aircraft, comprising at least one component according to the invention. Attached Figure Description

[0042] Other features and advantages of the invention will become apparent from the following detailed description, and with reference to the accompanying drawings, in order to understand it:

[0043] - Figure 1 This is a schematic perspective view of a propeller blade for an aircraft turbine engine, and it illustrates the invention.

[0044] - Figure 2 yes Figure 1 A magnified view of a portion, showing the root of the blade.

[0045] - Figure 3 yes Figure 1 A schematic exploded perspective view of the root of the blades in the image.

[0046] - Figure 4 yes Figure 1 A schematic perspective view of the main body of the root of the blades.

[0047] - Figure 5 yes Figure 1 Another schematic axial cross-sectional view of the root of the impeller and the guide bearing, the cross-sectional plane extending along the chord of the impeller blade.

[0048] - Figure 6 yes Figure 1 A schematic axial cross-sectional view of the root of the impeller and the guide bearing, wherein the cross-sectional plane extends transversely to the chord of the impeller blade.

[0049] - Figure 7 It is along Figure 5 Another schematic cross-sectional view of line VII-VII,

[0050] - Figure 8 yes Figure 1 A schematic diagram of the root of a blade and an axial cross-section of an embodiment of a pitch setting system for the blade, the pitch setting system including a retaining fork manufactured according to a first embodiment of the invention.

[0051] - Figure 9 yes Figure 8 A schematic perspective view of the cup portion of the system.

[0052] - Figure 10 yes Figure 8 A schematic perspective view of the dog-tooth ring system in the diagram.

[0053] - Figure 11 It is used for Figure 8 A schematic perspective view of the locking ring of the system.

[0054] - Figure 12 yes Figure 8 A schematic perspective view of the root of the impeller and a partial axial cross-section of the system, showing the first step of installation, wherein the upper portion of the cup is cut off to allow for better observation of the cup's interior.

[0055] - Figure 13 yes Figure 8 A schematic perspective view of the root of the impeller and a partial axial cross-section of the system, and the second installation step is shown.

[0056] - Figure 14 yes Figure 8 A schematic perspective view of the root of the impeller and a partial axial cross-section of the system, and the third installation step is shown.

[0057] - Figure 15 yes Figure 8 A schematic perspective view of the root of the impeller and a partial axial cross-section of the system, and the fourth installation step is shown.

[0058] - Figure 16 yes Figure 8 A schematic perspective view of the root of the impeller and a partial axial cross-section of the system, and the fifth installation step is shown.

[0059] - Figure 17 yes Figure 8 A schematic perspective view of the root of the impeller and a partial axial cross-section of the system, and the sixth installation step is shown.

[0060] - Figure 18 yes Figure 1 A schematic diagram of the root of a blade and an axial cross-section of a variant embodiment of a pitch setting system for the blade, the pitch setting system including a retaining fork manufactured according to a first embodiment of the invention.

[0061] - Figure 19 This illustrates a second embodiment of the retaining fork, and... Figure 8 Similar half-view,

[0062] - Figure 20 This illustrates a third embodiment of the retaining fork, and... Figure 8 Similar half-view,

[0063] - Figure 21 This is a schematic perspective view of a retaining fork manufactured according to a variant embodiment of the invention, showing a partial axial cross-section.

[0064] - Figure 22 This illustrates another variant embodiment of the retaining fork, and... Figure 21 A similar view. Detailed Implementation

[0065] Figure 1 The blade 10 of a propeller for an aircraft turbine engine is shown; the propeller may be ducted or unducted.

[0066] The whorl 10 includes blades 12 connected to the root 14.

[0067] The blade 12 has an aerodynamic profile and includes a ventral arch 12a and a stern arch 12b, which are connected by an upstream leading edge 12c and a downstream trailing edge 12d, the terms upstream and downstream referring to the flow of gas around the blade 12 during operation.

[0068] The blade 12 has a free upper end, referred to as the top, and a lower end connected to the root 14.

[0069] In the example shown, the blade 10 is made of composite material by an injection molding method known as Resin Transfer Molding (RTM). This method involves preparing a fiber preform 18 by three-dimensional weaving, then arranging the preform in a mold and injecting a polymerizable resin, such as epoxy, to impregnate the preform. After the blade 12 has cured and hardened, the leading edge 12c of the blade is typically reinforced by a metal sheath 20, which is assembled and attached, for example, by gluing.

[0070] The blade 10 here includes a sparsity 22, which includes a portion forming the core of the blade 12 and intended to be inserted into the preform 18 prior to resin injection, and a portion extending from the side opposite the top of the blade 12 to form a portion of the root 14 (referred to as body 24).

[0071] Preferably, the spar 22 is made of a 3D woven carbon fiber reinforced epoxy organic matrix composite material, wherein, at the height of the aerodynamic duct, the warp direction is primarily radially oriented, and the weft direction is primarily oriented along the chord of the blade 12. However, the spar can also be a mechanically more advantageous component made of different organic matrix composite materials (thermosetting, thermoplastic, or elastomers), which are reinforced with long fibers (carbon, glass, aramid, polypropylene) formed in different fiber arrangements (woven, braided, knitted, unidirectional).

[0072] Although not shown, the blade 12 may be hollow or solid and includes an inner cavity filled with a foam or honeycomb filler material. This filler material is mounted around the spar 22 and covered with a skin made of an organic matrix composite material to increase the impact resistance of the blade 12.

[0073] The sheath 20 can be made of titanium or titanium alloy, stainless steel, steel, aluminum, nickel, etc. The arched belly 12a or even the arched back 12b of the blade 12 can be covered with a polyurethane film to prevent corrosion.

[0074] The axis "A" is the extension axis of the impeller 10 and the blade 12, especially the setting axis "A" of the impeller 10, which is the axis around which the angular position of the impeller 10 is adjusted. This axis is usually also the radial axis, so it extends radially relative to the axis of rotation of the propeller equipped with the impeller 10.

[0075] As in Figure 8 As shown, the blade 10 is attached to the turbine engine hub 72 via the blade root 14 and pitch setting system 34, which will be described in more detail later. The hub 72 is here used as an annulus serving as a rotor disk. The hub 72 is equipped with a housing 73, which constitutes an aerodynamic fairing for the hub 72. The housing 73 includes an opening 75 for the blade 10 to pass through, such that the root 14 is accommodated within the housing 73, while the blade 12 extends radially outward from the housing 73.

[0076] The root 14 includes a main body 24, the main body having in Figures 3 to 7 The body 24 is best seen in a specific shape. The body 24 includes a spherical portion 32 connected to the blade 12 by an extension, which is radially narrower than the spherical portion 32 and is referred to as a columnar portion 30. Preferably, the body 24 is solid, i.e., the body has no hollow recessed portions.

[0077] In the embodiment shown in the accompanying drawings, the root portion 14 includes a metal sleeve portion 26 that at least partially encloses the body portion 24, and in particular the ball portion 32, which will be described in more detail later.

[0078] Preferably, the sleeve 26 is independent of the pitch setting system 34.

[0079] The root 14 is intended to be mounted in the hub 72 by a pitch setting system 34, which allows the blade 10 to pivot relative to the hub 72 about the blade setting axis "A".

[0080] The pitch setting system 34 includes a cup portion 58, which includes an annular wall 58a extending around a setting axis "A". The cup portion 58 serves as a pivot for the impeller 10 relative to the hub 72. The wall 58a includes a lower axial end closed by a bottom wall 58b and an upper axial end open through a channel 59a, which is radially defined by the upper end edge 59b of the wall 58a. The wall 58a gradually widens from bottom to top so that the root 14 of the impeller 10 can be mounted within the cup portion 58 by axial insertion in the direction of the setting axis "A". The cup portion 58 is integrally formed.

[0081] The wall 58a of the cup portion 58 is defined radially inward by the inner surface 59b.

[0082] An elastically deformable member 66 (e.g., a helical spring) extends about the setting axis “A” and is mounted inside the cup portion 58. The member 66 is axially abutted against the upper surface of the bottom wall 58b, located at the outer periphery of the surface in the illustrated example, and is configured to axially bias the root 14 of the blade 10 toward the outside of the cup portion 58 (i.e., toward the top side of the blade 10).

[0083] As in Figure 8 As can be seen, the cup portion 58 is designed to be pivotally mounted in the hub portion 72 about the setting axis "A". In particular, the cup portion is designed to support bearings 54 and 56, which ensure centering and guidance of the cup portion 58 relative to the hub portion 72 about the setting axis "A".

[0084] Bearings 54 and 56 may form part of the pitch setting system 34. In particular, at least one of the guide bearings may have an inner ring that is integrated into the cup portion 58.

[0085] The lower bearing 54 is an example of this, with its inner ring 54a integrated into the cup portion 58. In effect, this means that the cup portion 58 includes a raceway 54a on its outer periphery, on which the balls of the bearing 54 roll directly. This raceway includes an annular surface with a concave curved cross-section. This raceway is located at the lower end of the wall 58a and the cup portion 58. The outer ring 54b of the bearing 54 is attached to the housing 73, for example, by a shrink fit. Furthermore, advantageously, the cup portion 58 is designed to apply preload to the bearing 54.

[0086] The outer ring 56b of the bearing 56 is attached to the housing 73, for example, by a shrink fit. The inner ring 56a of the bearing engages with and around the free upper ends of the cup portion 58 and the wall 58a. This end of the wall 58a includes an outer cylindrical surface 76 for mounting the inner ring 56a and external threads for screwing on a nut 78, which is intended to be axially supported on the inner ring 56a to keep the inner ring axially fastened against the outer cylindrical shoulder 80 of the cup portion 58.

[0087] The wall 58a of the cup portion 58 gradually widens outward, allowing the ball portion 32 to be freely inserted by sliding axially into the cup portion 58. Therefore, it is necessary to provide a retaining member to axially attach the ball portion 32 into the cup portion 58, thereby ensuring the axial attachment of the impeller 10 relative to the hub portion 72. For this purpose, the cup portion 58 includes a device in its inner surface 59b configured to engage with a retaining ring 52, which forms the retaining member.

[0088] The retaining ring 52 extends around the setting axis "A" and is configured to be mounted around the root 14. The retaining ring 52 is configured to be mounted inside the cup portion 58 and to engage with the annular wall 58a of the root 14 and the cup portion 58, respectively, to ensure that the root 14 is axially held in the cup portion 58.

[0089] Different embodiments of the retaining ring 52 will be described in detail below.

[0090] The impeller 10 can also be rotatably fixed to the cup portion 58. The bottom wall 58b is here configured to mate with the free end 28 of the root 14 in a form-fitting manner, and thus with the free end 28 of the body 24, so that the cup portion 58 can be rotatably fixed to the root 14 about an axis. In this case, it should be understood that the bottom wall 58b includes a recess 60 having a non-circular, particularly rectangular, cross-section, and is configured to receive the end 28 (…). Figure 8 ).

[0091] According to the teachings of the present invention, the pitch setting system 34 includes a safety device for retaining the root 14 of the blade 10 within the cup portion 58 when the fixing member (in particular the retaining ring 52) can no longer perform its attachment function. This safety device makes it possible to prevent the blade 10 from colliding with the aircraft in the event of detachment.

[0092] For this purpose, at least one retaining fork 77 extends radially from the inner surface 59b of the cup portion 58 into a radial space “E” reserved between the wall 58a of the cup portion 58 and the root portion 14. The extension of the fork 77 is arranged axially opposite to the ball portion 32, thereby restricting the channel section 59a of the cup portion 58 to retain the root portion 14 of the impeller 10 within the cup portion 58 in the event of a failure of the component used to secure the root portion 14 in the cup portion 58. Thus, when the root portion 14 separates from the cup portion 58, the root is subjected to a radially oriented centrifugal force that tends to push the root portion out of the cup portion 58. The fork 77 forms a restrictive portion of the channel section 59a of the cup portion 58 that contacts the root portion 14. Therefore, the centrifugal force applied to the impeller 10 is transmitted to the hub portion 72 through the fork 77 and the cup portion 58 to retain the impeller 10 within the cup portion 58.

[0093] The fork 77 forms a dotted protrusion, which in one embodiment does not extend circumferentially around the setting axis "A" in a continuous manner.

[0094] exist Figure 21 In an alternative embodiment of the fork 77 shown, the fork 77 has the shape of a rotating wall. The fork configuration 77, as described below, is defined by a cross-section in a plane containing the setting axis "A".

[0095] exist Figure 22 In another variant embodiment of the fork 77 shown, the fork 77 is in the form of a segmental element of a rotating wall. The fork configuration 77, as described below, is defined according to a cross-section in a plane containing the setting axis "A".

[0096] As in Figure 8 As shown, the fork 77 is integrally formed with the support member 79, which is assembled and attached to the cup portion 58. The support member 79 includes an axial attachment protrusion 81 that abuts against the inner surface 59b of the cup portion 58, and the fork 77 extends radially from the axial attachment protrusion. More specifically, the fork 77 extends radially from the upper end of the attachment protrusion 81.

[0097] exist Figure 21 and Figure 22 In the embodiment shown, multiple attachment protrusions are distributed at multiple points surrounding the fork 77, forming a rotating wall or a segment element of the rotating wall. Figure 21 and Figure 22The sections shown do not include any attached protrusions.

[0098] The attachment protrusion 81 is attached to the wall 58a of the cup portion 58, for example, by a screw 97 and a nut 99 assembly. The nut 99 is made, for example, by pressing two rivets through the wall 58a of the cup portion 50 or through the attachment protrusion 81. For example, the nut 99 is installed with a gap in the plane of the wall through which the nut passes, and the screw 97 allows attachment by clamping. The diameter of the through hole 101 through which the screw 97 can pass is slightly larger than the diameter of the shank of the screw 97, so as to avoid shearing the screw 97 by keeping the shank away from the edge of the hole 101. Thus, attachment is generally achieved by fastening the screw 97 against the support.

[0099] The support member 79 is made of a metallic material such as steel, titanium or titanium alloy (e.g., TA6V), chromium-nickel-iron alloy or aluminum.

[0100] In the event of a failure in the fixing member of the root 14 in the cup portion 58, the fork 77 may bend to axially suppress displacement of the root 14 of the impeller 10. Therefore, the kinetic energy of the impeller 10 is converted into deformation energy of the fork 77. More specifically, the fork 77 has a first elbow 83a at its end for connection to the attachment protrusion 81. The fork 77 may bend due to deformation of this first elbow 83a.

[0101] To impart greater flexibility to the fork 77, the fork has a main extension 77a and an end extension 77b. The main extension is generally straight and oriented radially inward from the attachment protrusion 81. The end extension is also generally straight, but bends radially outward in the event of axial displacement of the root 14 of the impeller 10 to facilitate deformation of the fork 77. Specifically, the main extension 77a slopes toward the bottom of the cup 58. The end extension 77b extends radially toward the wall of the cup 58 from the connecting end of the end extension connected to the main extension 77a. The end extension 77b also slopes toward the bottom of the cup 58, extending generally parallel to the wall segment opposite the axial direction of the ball 32. Therefore, the fork 77 has a second elbow 83b, which is arranged at the connection between the main extension 77a and the end extension 77b.

[0102] The fork 77 is designed to contact the root 14 via a contact surface 85 formed by the lower surface of the end extension 77b. The contact surface 85 extends substantially parallel to the opposing wall section of the ball portion 32. Therefore, during axial displacement of the impeller 10, the contact surface area 85 in contact with the ball portion 32 is large enough to withstand pressure and hold the ball portion 32 within the cup portion 58.

[0103] During the axial displacement of the impeller 10, the ball portion 32 of the root 14 biases the fork portion 77 through the contact surface 85 of the ball portion, thereby causing the fork portion 77 to bend at the first elbow 83a and the second elbow 83b of the fork portion. Therefore, the impact on the root 14 may be absorbed more effectively.

[0104] In particular, the fork portion 77 is elastically deformable at least in a portion of the bent portion of the fork portion. For example, the fork portion 77 is elastically deformable throughout the entire bending movement portion of the fork portion.

[0105] Alternatively, the fork 77 is elastically deformable at the first part of the bending movement portion of the fork, so that the energy transmitted by the root 14 is absorbed by the plastic deformation of the fork 77 at the end of the bending movement portion of the fork.

[0106] According to Figure 8 In the first embodiment of the invention shown, at the attachment position of the root 14 of the impeller 10 in the cup portion 58, the fork portion 77 is arranged at an axial distance from the protruding section of the root 14. To prevent the impeller 10 from gaining excessive speed before the fork portion 77 decelerates it in the event of a malfunction of the retaining ring, preferably, the axial distance between the fork portion 77 and the ball portion 32 of the root 14 is reduced, for example, to less than 2 mm.

[0107] According to Figure 19 In the second embodiment of the invention shown, at the attachment position of the root 14 of the blade 10 in the cup portion 58, the fork portion 77 is arranged to be prestressed by bending against the protruding section of the root 14. Figure 7 In the diagram, the resting position of the fork 77 is shown by a dashed line. It can be seen that the fork 77 is pushed outward and upward against the elastic return force of the fork. This embodiment allows the fork 77 to absorb the kinetic energy of the blade 10 at the start of axial removal of the blade, before the blade has a chance to gain speed.

[0108] To improve damping when the blade 10 contacts the fork 77, the contact surface 85 of the fork 77 may be covered with a gasket (not shown), such as a gasket made of an elastomeric material.

[0109] Preferably, the support member 79 includes a plurality of forks 77, which are evenly distributed around the root 14 of the blade 10 to distribute force.

[0110] To facilitate the arrangement of the support member in the cup portion 58, the support member 79 is formed by a plurality of different sections 79a, 79b, each of which is independently attached to the cup portion 58. Each section 79a, 79b may be arranged to contact two adjacent sections 79a, 79b, or the sections may be arranged to be circumferentially spaced apart.

[0111] Each section 79a, 79b is equipped with at least one fork 77 so that the holding force of the blade 10 can be distributed around the cup section 58.

[0112] When the support portion is formed by multiple distinct sections 79a, 79b, each section 79a, 79b is radially positioned by supporting an annular segment abutting the inner surface 59b of the cup portion 58. Furthermore, the cup portion 58 includes at least one shoulder surface 87 extending radially inward from the inner surface 59b of the cup portion to axially support and receive each section 79a, 79b of the support member 79. More specifically, the upper end of the attachment protrusion 81 is axially supported against the shoulder surface 87. Thus, each section 79a, 79b is radially and axially positioned such that each fork 77 is correctly positioned relative to the ball portion 32.

[0113] Here, shoulder surface 87 is formed by the lower surface of edge 89, which extends radially inward from the upper end of cup portion 58. As will be explained later, in some embodiments of the pitch setting system 34, it is necessary to provide channels for inserting components such as retaining rings. In this case, edge 89 does not extend continuously around the entire circumference of cup portion 58, but is formed by discontinuous segmental elements, with circumferential spaces reserved between the discontinuous segmental elements for inserting said elements.

[0114] Advantageously, the support member 79 includes a radial plate 91 for attaching a platform 93 designed to close the relevant opening 75 of the housing 73 to provide better aerodynamic performance for the propeller. The attachment plate 91 is positioned at the upper end of the attachment protrusion 81. Here, the attachment plate extends above the upper end of the cup portion 58 to support the platform 93, which typically closes the entire opening 75. The plate 91 extends radially from an inner end located near the post portion 30 and perpendicular to the interior of the cup portion 58, while the outer end is positioned perpendicular to the exterior of the cup portion 58. The plate 91 extends just below the housing 73, such that the platform 93 is flush with the outer surface of the housing 73.

[0115] For example, plate 91 has an annular shape surrounding the setting axis "A". Plate 91 is made of multiple segment elements, for example, to facilitate the arrangement of the plate around the root 14. Each segment element may have at least one fork 77.

[0116] Therefore, the support member 79 serves not only as a safety device in case of a failure of the retaining ring 82, but also as a support for the platform 93. This allows for a reduction in the number of components constituting the propeller, thereby reducing the propeller's weight and simplifying its assembly.

[0117] Platform 93 can be made of metal or composite materials.

[0118] In order to adjust the position of platform 93 along the setting axis "A" so that the platform is flush with the outer surface of housing 73, a wedge 95 can be inserted between platform 93 and plate 91.

[0119] The implementation of the invention will now be described through two specific, non-limiting embodiments of the pitch setting system 34. In these two embodiments, as previously described, the body 24 of the root 14 has in Figures 3 to 7 The specific shape that is best seen in the middle.

[0120] The main body 24 roughly includes the above three parts, namely:

[0121] - Free end 28, the free end is located on the opposite side of blade 12,

[0122] - Column 30, the column is located on one side of blade 12, and

[0123] - Sphere 32, located between free end 28 and column 30.

[0124] In the example shown, the free end 28 has a roughly parallelepiped shape. Figure 7 As can be seen, this end 28 is offset from the pitch axis "A" for proper détrompage or indexage, which will be explained in more detail below.

[0125] As in Figure 5 and Figure 6 As shown, Pb is defined as a transverse plane, that is, a plane perpendicular to the setting axis "A", which passes approximately through the middle of end 28 measured along the setting axis "A". This plane Pb is referred to as the bottom plane or lower plane. Figure 7 The cross-sectional shape of end 28 in the plane Pb is shown. This cross-section, referred to as the bottom cross-section, has a value or area denoted as Sb (e.g., the maximum value or area) and is typically rectangular in shape in the example shown.

[0126] As will be described below, end portion 28 is configured to mate with system 34 for setting blade 10.

[0127] The column portion 30 has a relatively complex shape and can be considered to include:

[0128] - Two side wings 30a and 30b, located on the side of the convex belly 12a and the convex back 12b of the blade 12 respectively, converge toward each other along the setting axis "A" at the top of the blade 12.

[0129] - Two edges, namely upstream edge 30c and downstream edge 30d, are separated from each other along the setting axis "A" at the top of blade 12 (see...). Figure 4 and Figure 5 ).

[0130] Ph is defined as a transverse plane passing through the column 30 (specifically through the lower end of the column). This plane Ph is referred to as the height plane or upper plane. In this plane, the column may have a non-circular cross-sectional shape (e.g., elliptical, oblong, square, or rectangular). This cross-section, referred to as the height section, has a value or surface area (e.g., the maximum value or surface area) denoted by Sh.

[0131] The spherical portion 32 has a generally convex shape or a dome shape, which extends around the setting axis "A".

[0132] Pm is defined as the intermediate plane passing through the sphere 32, particularly at the portion of the sphere with the largest cross-section (denoted as Sm). This plane Pm is referred to as the intermediate plane. In this plane, although not restrictive, the sphere 32 may have a circular cross-sectional shape.

[0133] It should be understood that plane Pm lies between planes Pb and Ph. The cross-section of sphere 32 decreases from plane Pm (Sm) to plane Ph, and decreases further from plane Pm toward plane Pb. Therefore, it should be understood that Sm is greater than Sb and Sh. Furthermore, in the example described, Sh is greater than Sb.

[0134] The sleeve 26 here is made of two half-shells 26a and 26b, as in Figure 3 As can be seen, the two half-shells are assembled and attached to the main body 24, for example, one half-shell is on the side of the convex 12a of the blade 12, and the other half-shell is on the side of the convex back 12b of the blade 12. Thus, the half-shells 26a and 26b are joined at a joint plane that passes through the setting axis "A" and extends approximately parallel to the chord of the blade 12.

[0135] Advantageously, the sleeve 26 is preferably attached to the body 24 by adhesive bonding. The adhesive extends between the sleeve and the body 24 around the setting axis "A".

[0136] Preferably, the sleeve 26 is made of metal (e.g., steel, titanium, or titanium alloy, such as TA6V). The adhesive is, for example, an epoxy resin filled with thermoplastic joints or elastic nodules, or a fiber-reinforced epoxy resin. This adhesive bonding method is particularly suitable due to the large contact surface area between the cavity of the sleeve and the body 24 (which may be a composite material). The presence of an adhesive seal is advantageous because it allows minor shape defects to be corrected. The adhesive seal also prevents friction at the metal / composite material interface, thus increasing the service life of the impeller 10.

[0137] Several possible methods for assembling the sleeve 26 to the body 24 are envisioned. A first possible method is to intentionally maintain a gap between the two halves 26a and 26b of the sleeve 26 once the two halves are assembled, so that appropriate pressure can be applied when the sealant cures. The curing stage can be carried out in an autoclave, with the entire impeller 10 within a vacuum bag. However, this operation can also be performed in a press. However, the disadvantage of maintaining a gap between the two halves 26a and 26b is that the positioning of the two halves is more difficult to control, thus requiring rework of the outer surfaces.

[0138] A second possible approach is to assemble the half-shells by having one half-shell abut against the other half-shell around the body 24 without any existing gaps. This strategy is possible, for example, by machining a blank that has already been cut into two parts and held together during machining operations to ensure the geometry of the outer surface once the half-shells are reassembled. This allows the positioning and geometry of the outer surface of the sleeve 26 to be controlled without requiring additional machining after gluing. In any case, the relative position of the sleeve half-shells can be secured by locating pins or stops.

[0139] However, the presence of a sealant between the body 24 and the sleeve is not mandatory, although it is highly advantageous. Optionally, a prestressed washer (or spring) can be used between the sleeve and the composite body 24 to radially press the body 24 against the support surface of the sleeve. The geometry of the sleeve can also be used to slightly “clamp” the body 24 when the two halves of the sleeve are assembled around the ball 32. In this case, deformation of the sleeve generates prestress. Therefore, tools must be provided to hold this position before final assembly.

[0140] As in Figure 5 and Figure 6 As can be seen, the sleeve 26 covers and fits at least a portion of the ball portion 32 and the column portion 30, and has complementary shapes in the cross section of the ball portion 32 at the intermediate section Sm and in the cross section of the column portion 30 at the high section Sh.

[0141] More specifically, in the example shown, sleeve 26 comprises three parts:

[0142] -Lower end 36, the lower end is roughly ring-shaped (see...) Figures 5 to 7 And it extends around the free end 28 of the root 14.

[0143] - Upper end portion 38, extending at plane Ph and including two side lips 40, the two side lips being applied to the side wings 30a, 30b of the column portion 30, and

[0144] -Middle part 42, the middle part is applied to the ball part 32 and fits closely to the shape of the ball part.

[0145] The lip 40 is supported on the side wings 30a and 30b of the column 30, and the root 14 of the blade 10 is strengthened and its resistance to torsion around the axis A is enhanced.

[0146] Furthermore, the lips allow for energy absorption in the event of an impact on the impeller 10 (e.g., ingestion by a bird). Rounded corners may be present on these lips to prevent localized wear or damage to the body 24.

[0147] The inner surface of the sleeve 26 that contacts the body 24 serves as a support surface. Compared to a pin-fixed attachment, the support surface is maximized by utilizing the entire circumference of the bottom of the blade 10. In a pin-fixed attachment, only two different surfaces of the root 14 of the blade 10, located on the ventral and stern respectively, are supported on the support surface, while the surfaces of the root 14 of the blade 10 located on the leading and trailing edges are free. Furthermore, compared to a pin-fixed attachment, the support surface has a much greater height in the radial direction, which also contributes to a significant increase in the surface area of ​​the support surface. This large support surface allows for reduced contact pressure under all operating conditions.

[0148] The sleeve 26 includes two cylindrical surfaces 44, 46a for mounting shrink-fit rings 48, 50. The shrink-fit rings 48, 50 enable the half-shells 26a, 26b to be held abutting against each other and secured to the body 24. The shrink-fit rings 48, 50 extend about the setting axis "A".

[0149] Surface 44 is located on the lower end 36 and is oriented radially outward relative to the setting axis "A". This surface receives the ring 48 by a contraction fit, which engages from below and is axially supported on the cylindrical support surface located at the junction of the end 36 of the sleeve 26 and the intermediate portion 42.

[0150] Surface 46a is located on intermediate surface 42 and is oriented radially outward relative to the setting axis "A". This surface receives ring 50 by a contraction fit, which engages from above and is axially supported on a cylindrical support surface positioned close to plane Pm.

[0151] As can be seen, surface 46a is positioned adjacent to cylindrical surface 46b, which is designed to receive retaining ring 52, as described below.

[0152] In the example shown, surfaces 44 and 46a, and rings 48 and 50, have different diameters. The diameter of surface 46a is larger than that of surface 44, and therefore the diameter of ring 50 is larger than that of ring 48.

[0153] Surfaces 46a and 46b may have the same or different diameters. For example, the diameter of surface 46b may be slightly smaller than that of surface 46a. This is especially true when the ring 50 is to be mounted relative to surface 46b with a predetermined radial clearance.

[0154] from Figure 5 and Figure 6 It can be seen that ring 50 is located between plane Ph and plane Pm, and ring 48 is located between plane Pm and plane Ps.

[0155] Figure 5 and Figure 6 The positions of rings 48, 50 and planes Pm, Ph, Ps relative to rolling bearings 54, 56 are also shown, which extend around the setting axis "A" and root 14.

[0156] Here, there are two bearings, 54 and 56, namely the lower bearing 54 and the upper bearing.

[0157] Bearings 54 and 56 are ball bearings. In the example shown, the bearings have different diameters, and the balls in the bearings also have different diameters.

[0158] Bearing 54 extends generally between plane Pm and plane Pb, and thus extends around the lower portion of ball portion 32. The bearing also extends around ring 48. The diameter of bearing 54 is smaller than that of bearing 56, and the diameter of the balls in bearing 54 is larger than that in bearing 56.

[0159] Bearing 54 is also of the angular contact type. In the example shown, the bearing point or bearing surface of the ball on the raceway of the ball rings 54a, 54b is located on the truncated conical surface S1, which extends along the setting axis "A", and the maximum diameter of the truncated conical surface is located on the top side of the impeller 10.

[0160] Bearing 56 extends generally between plane Pm and plane Ph, and thus extends around the upper portion of ball portion 32. The bearing also extends around ring 50. Bearing 56 is also of angular contact type. In the example shown, the bearing points or bearing surfaces of the balls on the raceways of the ball rings 56a, 56b are located on a truncated conical surface S2, which extends along the setting axis "A," and the maximum diameter of this truncated conical surface is located on the free end side of the root 14 of the impeller 10.

[0161] Because the portion of the support surface located in height between the intermediate section and the high section is inside the cup portion 58, unlike existing technology where the attachment is fixed by a pin integrated into the pivot, the position of the intermediate section between the two bearings 54, 56 is highly advantageous in terms of overall radial dimension. This helps to reduce the overall radial dimension of the mounting system 34.

[0162] Figures 8 to 17 A first embodiment of the pitch setting system 34 is shown, particularly a first embodiment of the retaining ring 52. Figure 18 An alternative embodiment of the pitch setting system 34 and the ring is shown.

[0163] The pitch setting system 34 includes a cup portion 58, which includes an annular wall 58a extending around the setting axis "A". The wall 58a includes a lower axial end and an upper axial end, the lower axial end being closed by a bottom wall 58b, and the upper axial end being open and configured such that the root 14 of the blade 10 can be mounted within the cup portion 58.

[0164] The bottom wall 58b is configured to engage with the free end of the root 14 in a shape-fitting manner, and thus with the end 28 of the body 24, so that the cup 58 can be rotatably fixed to the root 14 about the axis.

[0165] In this context, it should be understood that the bottom wall 58b includes a recess 60 having a non-circular, particularly rectangular, cross-section, and is configured to receive the end 28. Figure 8 ). For example in Figure 5 As can be seen, the recess 60 is in a similar manner to the end portion 28 (see [reference]). Figure 7 It is eccentric relative to the setting axis "A". This eccentricity allows for rotation and proper fixation when the root 14 is inserted and installed in the cup portion 58, and ensures that the end 28 has only one engagement position in the recess 60.

[0166] The recess 60 is located on the upper or inner surface of the bottom wall 58b of the cup portion 58, so the recess is located inside the cup portion 58 and is oriented to the side of the root portion 14.

[0167] The pitch setting system 34 generates torque at the root 14 of the blade 10, which counteracts the torsional moment generated by aerodynamic forces and centrifugal forces. The end 28 of the root 14 can be enclosed in the sleeve 26 like the rest of the body 24 of the root 14. In this case, the end of the root will also have a non-circular shape to limit the rotation of the end of the root. However, as mentioned above, advantageously, this end of the body 24 protrudes from the sleeve to directly force the body 24 to rotate. This provides a more direct force path, allowing the torsional moment to be applied directly to the body 24. The dimensions of the bottom section are strictly smaller than the maximum dimensions of the intermediate section, thus limiting the total circumferential dimension to this height. As a result, the total circumferential dimension of the sleeve at this height is also smaller than the total circumferential dimension at the intermediate section. This allows for a reduction in the diameter of the lower bearing below the intermediate section. Therefore, the root 14 of the blade 10 can be integrated at a lower position, which greatly reduces the theoretical hub ratio associated with the integration of the root 14. Those skilled in the art know that, in particular, a low hub ratio improves engine performance, making the engine more compact and therefore lighter. This last point is a very important advantage of this technical solution compared to competing products, which typically have a sleeve with a cylindrical external shape.

[0168] The bottom wall 58b includes a lower surface or an outer surface located on the opposite side of the root 14 and includes a cylindrical extension 62 extending along the setting axis "A" and including an external thread or external straight spline 64 for rotatably connecting the pitch setting system 34 to a pitch changing mechanism (not shown), which is shared for different pitch setting systems 34 and blades 10 of the propeller.

[0169] An elastically deformable member 66 (e.g., a helical spring) extends about the setting axis “A” and is mounted inside the cup portion 58. The member 66 is axially abutted against the upper surface of the bottom wall 58b, located at the outer periphery of the surface in the illustrated example, and is configured to axially bias the root 14 of the blade 10 toward the outside of the cup portion 58 (i.e., toward the top side of the blade 10).

[0170] Component 66 is supported on the cylindrical support surface 68 of sleeve 26. In the example shown, component 66 is centered by engaging the upper end of the component with the cylindrical edge 70 of the sleeve and engaging the upper end of the component around the cylindrical edge of the sleeve, and engaging the lower end of the component with the cylindrical edge of the cup 58 and engaging the lower end of the component around the cylindrical edge of the cup, the cylindrical edge of the cup being located at the outer periphery of the bottom wall 58b.

[0171] Component 66 extends here around the shrink-fit ring 48.

[0172] exist Figure 8 As can be seen, the cup portion 58 is designed to support the bearings 54 and 56, which ensure that the cup portion 58 is centered and guided relative to the hub portion 72 around the set axis "A".

[0173] Bearings 54 and 56 may form part of the pitch setting system 34. In particular, at least one of the guide bearings may have an inner ring that is integrated into the cup portion 58.

[0174] The lower bearing 54 is designed such that its inner ring 54a is integrated into the cup portion 58. In effect, this means that the cup portion 58 includes a raceway 54aa on its outer periphery, on which the balls of the bearing 54 roll directly. This raceway includes an annular surface with a concave curved cross-section. This raceway is located at the lower end of the wall 58a and the cup portion 58. The outer ring 54b of the bearing 54 is attached to the hub portion 72, for example, by a shrink fit. Furthermore, advantageously, the cup portion 58 is designed to apply preload to the bearing 54.

[0175] The outer ring 56b of the bearing 56 is attached to the hub 72, for example, by a shrink fit. The inner ring 56a of the bearing engages with and around the free upper ends of the cup 58 and the wall 58a. This end of the wall 58a includes an outer cylindrical surface 76 for mounting the inner ring 56a and an external thread for screwing on a nut 78, which is designed to be axially supported on the inner ring 56a to keep the inner ring axially secured against the outer cylindrical shoulder 80 of the cup 58.

[0176] The wall 58a of the cup portion 58 also includes a device configured to cooperate with the aforementioned retaining ring 52 in the inner surface 59b of the wall.

[0177] The retaining ring 52 extends around the setting axis "A" and is configured to be mounted around the root 14. The retaining ring 52 is configured to be mounted inside the cup portion 58 and to engage with the annular wall 58a of the root 14 and the cup portion 58, respectively, to ensure that the root 14 is axially held in the cup portion 58.

[0178] exist Figures 8 to 17 In one embodiment, the retaining ring 52 is a canine ring, which includes an outer canine portion 84 configured to engage with a complementary inner canine portion 82 of the annular wall 58a of the cup portion 58.

[0179] The teeth 82 of cup part 58 are in Figure 9 This is best seen in the diagram. These teeth are evenly spaced around the setting axis "A". In the non-limiting example shown, there are six teeth. For example, each tooth has an angled extension around the setting axis "A" at an angle between approximately 20° and 30°.

[0180] Each tooth in the tooth portion 82 includes a groove 86 circumferentially oriented relative to the setting axis "A" on its inner circumference. The groove 86 in the tooth portion 82 forms a discontinuous valley around the setting axis "A".

[0181] Dog tooth ring Figure 10 The best observation is that the teeth 84 of the dog-tooth ring are evenly spaced around the setting axis "A". In the non-limiting example shown, there are six teeth. For example, each tooth has an angled extension around the setting axis "A" between about 20° and 30°.

[0182] Tooth 84 is complementary to tooth 82 and is configured to engage with these teeth 82 via a dog-tooth engagement. Dog-tooth engagement is a well-known mounting method in the aerospace field, and the mounting method will be illustrated by [details omitted]. Figures 12 to 17 As shown.

[0183] As stated above, and as in Figure 9 As shown, in this configuration, the edge 89 of the cup portion 58 is formed as segmental elements spaced apart circumferentially to allow the teeth 84 of the ring 52 to pass through. The segmental elements of the edge 89 are not necessarily arranged uniformly with the teeth 82 of the cup portion 58; the segmental elements of the edge may be angled away from the teeth of the cup portion. This allows for, for example, providing a means to retain the ring 52 within the cup portion 58 in the event of accidental removal. Figures 12 to 17 The portion of the cup 58 including the edge 89 is not shown in the image to allow for a better observation and explanation of the operation of the pitch setting system 34.

[0184] The ring 52 includes an inner cylindrical surface 52a, which is designed to engage with the aforementioned surface 46b of the sleeve 26 by sliding.

[0185] Ring 52 includes a second set of teeth 88 that extend axially upward from the upper surface 89 of ring 52 on the top side of impeller 10. These teeth 88 are also evenly spaced around the setting axis "A". In the example shown, there are six teeth 88. The teeth 88 may be staggered relative to teeth 84, i.e., the circumferential space between teeth 88 and teeth 84 is axially aligned. As a non-limiting example, each tooth 88 has an angled extension around the setting axis "A" between approximately 10° and 20°.

[0186] Each tooth in the tooth portion 88 includes a groove 90 circumferentially oriented relative to the setting axis "A" on its inner circumference. The grooves 90 in the tooth portion 88 form discontinuous grooves around the setting axis "A".

[0187] Figure 11A locking ring portion 92 is shown, which is configured to engage axially between the dog teeth portions 82 and 84 to prevent the ring 52 from rotating within the cup portion 58.

[0188] The ring portion 92 includes sliders 94, and in the non-limiting example shown, the number of sliders is six. The sliders are designed to engage in the inter-tooth space extending between the teeth 82 and the teeth 84. Therefore, it should be understood that these sliders 94 have a shape complementary to the shape of these spaces and are evenly spaced around the setting axis "A".

[0189] In the example shown, sliders 94 are secured to each other by bridges 96 extending circumferentially between them. There are five bridges 96, each extending between two adjacent sliders 94. Two sliders of 94 are intentionally not connected by bridges, leaving the ring 92 open. This simplifies installation when the ring is installed in the pitch setting system 34 by allowing the sliders to move apart or toward each other.

[0190] Each slider in slider 94 includes a groove 98 circumferentially oriented relative to the setting axis "A" on its inner circumference. The groove 98 in slider 94 forms discontinuous valleys around the setting axis "A".

[0191] The pitch setting system 34 also includes only... Figure 17 The visible ring-shaped buckle 100.

[0192] The snap ring 100 is installed in the cup portion 58 to axially retain the locking ring 9 within the cup portion 58. The snap ring 100 can also be separated or opened to facilitate its installation, and the snap ring is designed to engage in the groove 86 of the toothed portion 82 of the cup portion 58 and the groove 98 of the slider 94 of the ring portion 92 when all the grooves 86, 98 are located in the same plane perpendicular to the setting axis "A" and are arranged circumferentially relative to each other to form a complete valley around the setting axis "A" (see [reference]). Figure 16 and Figure 17 ).

[0193] Now refer to Figures 12 to 17 , Figures 12 to 17 It shows the method for dealing with the situation in Figure 1 The impeller 10 shown in the figure and in Figure 8 The method for installing the components formed by the pitch setting system 34 shown in the figure.

[0194] exist Figure 12In the first step shown, the root 14 of the impeller 10 is engaged in the cup 58 of the pitch setting system 34 by axial translation along the setting axis "A" until the end 28 of the body 24 of the root 14 engages in the recess 60 of the cup 58. As can be seen in the figure, the shrink fitting ring has been restrictedly installed around the post 30 of the body 24 of the root 14. Although not shown in the figure, when the root 14 is inserted into the cup 58, the member 66 ( Figure 8 () is compressed.

[0195] exist Figure 12 and Figure 13 In the second step shown, the shrink-fit ring is positioned at an angle around the setting axis "A" such that the teeth 84 of the shrink-fit ring are aligned with the space between the teeth 82 of the cup portion 58. Then, the ring 52 is axially translated within the cup portion 58 until the ring 52 engages on the surface 46b of the sleeve portion 26, and the teeth 84 are located directly below the teeth 82, as shown in... Figure 13 As shown in the diagram, the groove 90 provided on the teeth can be used to clamp the ring 52 with a suitable tool.

[0196] exist Figure 13 and Figure 14 In the third step shown, ring 52 is rotated and displaced about the setting axis "A" so that the teeth 82, 84 are axially aligned with each other. In the example shown, the angular displacement is approximately 25° to 30° due to the angled extension of the teeth. Teeth 88 can be used to clamp ring 52 and rotate the ring using the aforementioned tool. Member 66 (not shown) axially biases root 14 outward from cup 58 so that teeth 84 axially abut against teeth 82. Thus, root 14 is axially held within cup 58 and pitch setting system 34. During operation, the centrifugal force applied to blade 10 is transmitted to cup 58 through teeth 82, 84, and these forces are directly absorbed by bearing 54, whose inner ring 54a is integrated into cup 58.

[0197] exist Figure 15 and Figure 16 In the fourth step shown, the ring 92 is positioned at an angle around the setting axis "A" such that the slider 94 of the ring is aligned with the space between the teeth 82 and 84. Then, the ring 92 is axially translated within the cup 58 until the slider 94 engages in these spaces. Thus, the bridge 96 can rest against the teeth 84 of the ring 52. Therefore, the ring 92 prevents any rotation of the ring 52 within the cup 58.

[0198] exist Figure 17 In the final step shown, the snap ring 100 is engaged in the circumferentially aligned grooves 86, 98. The snap ring 100 prevents accidental disassembly of the ring portion 92.

[0199] Then, sections 79a and 79b of the support member 79 are positioned in the cup portion 58. Each section 79a and 79b is introduced into the space "E" radially retained between the wall 58a and the column portion 30 of the cup portion 58. Each section 79a and 79b is then positioned by radially pressing each section against the inner annular surface 59b of the cup portion 58 and axially upward pressing it against the shoulder surface 87 of the edge 89. The sections 79a and 79b are then attached in position, for example, by screws and crimp nuts.

[0200] exist Figure 8 In the embodiment shown, the fork 77 extends axially over the ball 32 but not over the retaining ring 52.

[0201] Alternatively, such as in Figure 20 As shown, the free end of the fork 77 extends axially opposite to the upper surface of the retaining ring 52. Therefore, the fork 77 also participates in retaining the retaining ring 52 within the cup 58.

[0202] It should be understood that the removal of the blade 10 is performed by executing the above steps in reverse order. It should also be understood that one of the fundamental steps in installing and removing the root 14 is the retaining ring 52. This ring 52 can be manipulated from outside the turbine engine, which is particularly advantageous during maintenance operations. The blade 10 can be removed from the propeller by removing and discarding a minimal number of components.

[0203] Reference Figure 18 , Figure 18 An alternative embodiment of the retaining ring 52' is shown. The ring 52' has a wedge-shaped cross-section and is configured to be axially biased outward from the cup portion 58 under centrifugal force during operation, and to keep the root portion 14 of the impeller 10 axially secured by the wedge effect.

[0204] In the example shown, ring 52' is generally trapezoidal in its axial half-section and includes a lower surface 102 and two side surfaces (inner surface 104 and outer surface 106, respectively). Surfaces 102 to 106 are annular and extend about the setting axis "A".

[0205] The ring 52' is engaged in the cup portion 58 around the root portion 14, and is axially supported on the shrink-fit ring 50 by the surface 102 of the ring via the washer 108.

[0206] The outer surface 106 of the ring engages with the complementary ring 110 by axial support and sliding. The complementary ring is installed inside the cup portion 58 and around the ring 52'.

[0207] The ring 52' is segmented and formed by multiple sections arranged around the setting axis "A" at a certain circumferential distance from each other. As a non-limiting example, the number of sections is six, and the sections are evenly distributed around the setting axis "A".

[0208] Finally, the nut 112 is screwed onto the internal thread at the upper end of the cup portion 58 and engages with the inner surface 104 of the ring 52' by support and axial sliding.

[0209] Tightening and securing the nut 112 causes axial displacement of the portion of the ring 52' resting on the washer 108, and causes these portions to be radially biased against the ring 110, which has a complementary shape. Thus, any installation clearance is eliminated.

[0210] The sleeve 26 includes a cylindrical shoulder 114, which rests against a complementary cylindrical shoulder 116 of the cup 58 at the junction between the middle portion 42 and the lower end of the sleeve 26. This variation is intended, in particular, to absorb centrifugal force to retain the impeller 10, and replaces the aforementioned member 66 by directly applying prestress between the sleeve 26 (and therefore the root 14 of the impeller 10) and the inner ring 54a of the bearing 54.

[0211] As in Figure 18 As shown, the support member 79, which includes the fork 77 and supports the plate 95, is of course applicable to this embodiment.

[0212] Other variant embodiments, not shown, are possible, including:

[0213] The half-shells 26a and 26b of the sleeve 26 can be assembled to the main body 24 by bolting, riveting, welding, etc.

[0214] The adhesive used to connect the sleeve 26 to the body 24 can be an epoxy resin, but it can also be an elastomer or thermoplastic resin. A non-adhesive film can also be used to allow relative movement while limiting frictional wear.

[0215] Still on the topic of the sleeve / body interface 24, multiple technical solutions from those proposed schemes can also be combined (gluing, applying prestress by washers or springs, applying prestress by the geometry of the sleeve); these solutions can be combined independently of the gap between the two parts of the sleeve;

[0216] Although not very advantageous, the radial position of the bearing that ensures the centrifugal retention of the impeller 10 can be opposite to the radial position of the bearing that ensures the absorption of the bending moment generated by aerodynamic forces and centrifugal forces.

[0217] In all these embodiments, when the retaining rings 52, 52' are no longer in a state of securing the root 14 of the impeller 10, the ball portion 32 is axially displaced outward along the setting axis "A". The ball portion 32 contacts the fork portion 77, causing deformation of the fork portion, which sufficiently decelerates the impeller 10, allowing it to be held within the cup portion 58 by the deformed fork portion 77. The centrifugal force applied by the impeller 10 is transmitted to the hub portion via the attachment protrusion 81, which axially supports against the shoulder surface 87, thus the shoulder surface transmits the centrifugal force to the cup portion 58, and the cup portion itself transmits the force to the hub portion 72 via rolling bearings 54, 56. In this way, the centrifugal force does not pass through the attachment screws of the support member 79, which are received in their respective orifices with sufficient radial clearance.

Claims

1. An assembly for an aircraft turbine engine, the assembly comprising a ductless propeller blade (10) and a system (34) for setting the pitch of the blade (10), the assembly comprising: - Blade (10), the blade including a root (14) intended to be attached to the hub (72) of the ductless propeller and intended to be received in a relevant opening (75) of the outer casing (73) of the hub (72), the root (14) having a spherical section (32). - A system (34) for setting the pitch of the blade (10) about a setting axis (A), the system (34) including a cup (58) intended to be arranged within the housing (73), the cup including an open, gradually widening upper end for axially inserting the root (14) into an annular wall (58a) of the cup (58), and the root (14) of the blade (10) being axially attached to the cup by a fixing member (52) attached to the cup (58), the cup (58) being intended to be pivotally mounted relative to the hub (72) about the setting axis (A); - At least one retaining fork (77) extends radially from the annular wall (58a) of the cup (58) into a radial space (E) between the annular wall (58a) of the cup (58) and the root (14), the retaining fork (77) being arranged axially opposite to the spherical segment (32), the retaining fork (77) being able to retain the root (14) of the impeller (10) within the cup (58) by contacting the spherical segment (32) in the event of a failure of the fixing member used to attach the root (14) to the cup (58). The characteristic feature is that the retaining fork (77) can bend in the event of a failure of the fixing member (52) for fixing the root (14) in the cup (58) to axially suppress the displacement of the root (14) of the blade (10).

2. The component according to claim 1, characterized in that, The retaining fork (77) is integrally formed with the support member (79), which is assembled and attached to the cup (58).

3. The component according to claim 2, characterized in that, The support member (79) includes an axially attached protrusion (81) that abuts against the inner surface (59b) of the cup portion (58), and the retaining fork portion (77) extends radially from the axially attached protrusion.

4. The component according to claim 3, characterized in that, The support member (79) includes a radial plate (91) for attaching a platform (93) intended to close a relevant opening (75) in the housing (73), the radial plate (91) being disposed at the upper end of the axial attachment protrusion (81) and extending above the upper end edge of the cup portion (58).

5. The component according to claim 4, characterized in that, The retaining fork (77) has a main extension (77a) and an end extension (77b), the main extension being radially inwardly oriented from the axially attached protrusion (81), and the end extension being radially outwardly bent in the event of axial displacement of the root (14) of the blade (10) to facilitate deformation of the retaining fork (77).

6. The component according to any one of claims 1 to 3, characterized in that, The retaining fork (77) can elastically bend and deform at least a portion of the bending movement of the retaining fork.

7. The component according to any one of claims 1 to 3, characterized in that, At the attachment position of the root (14) of the blade (10) in the cup (58), the retaining fork (77) is arranged at an axial distance from the spherical segment (32) of the root (14).

8. The component according to any one of claims 1 to 3, characterized in that, At the attachment position of the root (14) of the blade (10) in the cup (58), the retaining fork (77) is arranged to be prestressed by bending against the spherical section (32) of the root (14).

9. The component according to claim 2 or 3, characterized in that, The component includes a plurality of retaining forks (77) that are evenly distributed around the root (14) of the blade (10).

10. The component according to claim 2 or 3, characterized in that, The support member (79) is made of a plurality of different sections (79a, 79b), each of which is independently attached to the cup portion (58).

11. The component according to claim 2 or 3, characterized in that, The cup portion (58) includes a shoulder surface (87) that extends radially inward from the inner surface (59b) of the cup portion (58) and axially upward supports the support member (79).

12. The component according to claim 11, characterized in that, The support member (79) is attached to the cup portion (58) by an attachment screw (97) received in a through hole (101) having a diameter greater than that of the shank of the attachment screw. The attachment screw (97) is screwed into a nut (99) and is installed to have radial movement space in the through hole (101) of the cup portion (58) or in the through hole (101) of the support member (79), such that the axial force applied to the retaining fork (77) is transmitted upward only through the shoulder surface (87) against which the support member (79) abuts.

13. The component according to any one of claims 1 to 3, characterized in that, The fixing member is formed by a fixing ring (52, 52') extending about the setting axis (A) and configured to be mounted around the root (14). The fixing ring (52, 52') is configured to be mounted in the cup (58) and engage with the annular wall (58a) of the root (14) and the cup (58) respectively to ensure that the root (14) is axially held in the cup (58).

14. The component according to claim 13, characterized in that, The free end of the retaining fork (77) extends axially opposite to the upper surface of the retaining ring (52).

15. A turbine engine comprising at least one component according to any one of claims 1 to 14.

16. The turbine engine of claim 15, wherein the turbine engine is a turbine engine for an aircraft.

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