System for controlling the pitch of propeller blades of a turbine engine of an aircraft

Abstract

A system (34) for controlling the pitch of a propeller blade (10) of an aircraft turbine engine is disclosed, characterized in that the system comprises: - a cup-shaped portion (58) having an annular wall (58a) extending about an axis (A) intended to set the pitch of the blade, the annular wall (58a) having a lower axial end enclosed by a bottom wall (58b) and an open upper axial end configured such that the root (14) of the blade (10) can be mounted within the cup-shaped portion (58); and - a retaining ring (152) extending about the axis (A) and configured to be mounted around the root (14), the retaining ring (152) being a double-claw clutch ring comprising two annular rows of external claw teeth (154, 156), the two annular rows of external claw teeth constituting an active claw tooth and a safety claw tooth, respectively.

Description

Technical Field

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

[0002] The prior art specifically includes documents FR-A1-3 017 163 and FR-A1-3 080 322.

[0003] Aircraft turbine engine propellers can be ducted (e.g., in the case of a fan) or non-ducted (e.g., in the case of an open rotor architecture).

[0004] The propeller includes blades, which can have a variable pitch. The turbine engine then includes a mechanism that allows the pitch angle of the blades 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 disciplines 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 constraints imposed by static and dynamic loads), and limit mass and acoustic characteristics. Specifically, improvements in propeller aerodynamic performance tend to increase the bypass ratio (BPR), which translates to an increase in the propeller's outer diameter, and consequently, an increase in blade span. However, the increase in BPR occurs simultaneously with a decrease in the fan pressure ratio (FPF). Therefore, pitch-changing systems (variable-pitch blades) are typically required to make the propeller operable throughout its flight domain.

[0006] Various techniques exist for attaching variable-pitch propeller blades and for controlling the angular pitch of such blades. However, these techniques are relatively complex and expensive. Furthermore, in the event of blade problems, particularly damage, especially when the propeller is not tubular, these techniques cannot guarantee that the blades will remain radially outward relative to the propeller's axis of rotation.

[0007] In the event of a failure in the retaining mechanism for the propeller blades, ensuring that the blades are held in place to prevent them from protruding outwards and impacting the fuselage of the aircraft equipped with turbine engines is particularly important. This safety feature, known as "failsafe," is not always present in current technology control systems. Control systems that include this feature typically include components that are themselves easily detached and could impact the aircraft's fuselage. The larger and denser these components are, the greater the risk of fuselage damage and the greater the need for specific protective shields, which affects the aircraft's mass and thus its performance.

[0008] Therefore, a control system technology that integrates simple and effective safety functions is needed. Summary of the Invention

[0009] This invention relates to a system for controlling the pitch of propeller blades in an aircraft turbine engine, characterized in that the system comprises:

[0010] - A cup-shaped portion, comprising an annular wall extending about an axis intended to set the pitch of the impeller, the annular wall including a lower axial end enclosed by a bottom wall and an open upper axial end, the upper axial end being configured such that the root of the impeller can be mounted inside the cup-shaped portion, the bottom wall being configured to mate with the free end of the root in a form-fitting manner, such that the cup-shaped portion is rotationally secured to the root about the axis.

[0011] - A retaining ring, extending about the axis and configured to be mounted around the root, is configured to be mounted within the cup-shaped portion and engage with the annular walls of both the root and the cup-shaped portion to ensure axial retention of the root within the cup-shaped portion.

[0012] Furthermore, the retaining ring is a double-claw clutch ring, which includes two annular rows of outer claw-shaped teeth. The first row of teeth is configured to engage with complementary first inner claw-shaped teeth of the annular wall of the cup-shaped portion via a claw clutch, and engages with these teeth via an axial support portion to ensure the root is retained in the cup-shaped portion. The second row of teeth is configured to engage with complementary second inner claw-shaped teeth of the annular wall of the cup-shaped portion via a claw clutch, and is spaced apart from these teeth by an axial clearance to ensure safety in the event of a failure of the first row of teeth.

[0013] In this patent application, the double-claw clutch ring is defined as a ring equipped with two annular rows of external claw-shaped teeth. Each row of teeth is capable of engaging with a row of complementary internal teeth of a cup-shaped portion of the system via the claw clutch. The claw clutch is a device for mounting one component into another through two displacements of the components (by translating and then rotating one component relative to the other). One component engages with the other component by axial translation until the teeth move from a position above each other to a position below each other. This is achieved by aligning the teeth of one component with the inter-tooth space of the other component so that the components can engage with each other. The components are then displaced about their axis and rotated relative to each other, such that the teeth of the components are substantially axially aligned and can engage with each other via axial abutments.

[0014] The claw-shaped teeth in the first row of the retaining ring have the function of ensuring that the root is axially held in the cup-shaped part, and for this purpose, the complementary internal teeth of the axial support part and the cup-shaped part are engaged.

[0015] The claw-shaped teeth in the second row of the ring are designed to ensure fail-safe safety in the event of a failure of the teeth in the first row.

[0016] In other words, the retaining ring has claw-shaped teeth (first row) for holding the impeller root in place, specifically for the active or primary row and for the passive or secondary row (second row). These passive or secondary row claw-shaped teeth are not active during normal operation but are used in case of a failure in the active row. This redundancy ensures optimal safety at the impeller root without requiring modifications to the main system or additional components. Therefore, adding safety features to the system does not result in significant changes to the system or its overall dimensions.

[0017] Therefore, the object of this invention is to incorporate a safety element into the design of the attachment at the blade root. This safety element includes not only a secondary backup force path that prevents the blade from being released in the event of a failure in the primary holding system, but also fault detection for fan imbalance caused by a failure in the primary holding system. In practice, when the primary claw fails, the aforementioned clearance is consumed, and the blade is held by the secondary claw. When the radial position of the blade changes, this causes a detectable fan imbalance, indicating a problem.

[0018] The system according to the invention may include one or more of the following features, either individually or in combination:

[0019] - The first row of teeth is the upper row of teeth, which is designed to be located on one side of the blade of the impeller. The second row of teeth is the lower row of teeth, and therefore, the second row of teeth is designed to be located on one side of the root of the impeller.

[0020] - The second row of teeth is the upper row of teeth, which is designed to be located on one side of the blade of the impeller. The first row of teeth is the lower row of teeth, and therefore, the first row of teeth is designed to be located on one side of the root of the impeller.

[0021] - The first row of teeth and the second row of teeth are axially spaced apart from each other by a space designed to accommodate the first inner tooth or the second inner tooth, and the axial dimension of the space is greater than the axial thickness of these inner teeth.

[0022] - The axial thickness of the teeth in the first row is greater than the axial thickness of the teeth in the second row.

[0023] - The teeth in the first row and the teeth in the second row have essentially the same inner diameter and the same outer diameter;

[0024] - The retaining ring includes an inner cylindrical surface at its inner periphery, which is configured to engage with an outer cylindrical surface that is complementary to the root of the impeller or an element mounted to the root during the double-claw clutch, and the inner cylindrical surface is located inside the first row of teeth or even the second row of teeth.

[0025] - The axial dimension of the inner cylindrical surface is between 90% and 100% of the axial thickness of the teeth in the first row or the maximum axial thickness of the retaining ring.

[0026] - An upper bearing is mounted around the upper part of an annular wall, the upper part of which includes the first tooth and the second tooth at the inner periphery of the upper part and includes threads at the outer periphery of the upper part. A nut is tightened onto the threads and is axially supported on the outer ring of the bearing.

[0027] --The ring includes a truncated conical surface at its inner periphery, which is at least partially complementary to the shape of the root;

[0028] --The ring is segmented and includes multiple corner segments arranged side by side around the axis;

[0029] --The system also includes:

[0030] - A lower rolling guide bearing, which extends about the axis and is mounted around the lower portion of the annular wall;

[0031] - An upper rolling guide bearing, which extends about the axis and is mounted around the upper portion of the annular wall;

[0032] --At least one of the guide bearings has an inner ring integrated into the cup-shaped portion;

[0033] --At least one of the guide bearings is an angular contact bearing;

[0034] --The concave portion is eccentric relative to the pitch setting axis;

[0035] --The system also includes an elastically deformable member that extends about a pitch setting axis and is mounted inside the cup-shaped portion. The member is axially supported on the bottom wall and configured to axially bias the root of the impeller toward the outside of the cup-shaped portion.

[0036] --The system also includes a locking ring and an annular retainer. The locking ring is configured to engage axially between the inner and outer claw teeth to prevent the claw clutch ring from rotating within the cup-shaped portion. The annular retainer is mounted in the cup-shaped portion to axially block the locking ring within the cup-shaped portion.

[0037] --The cylindrical section is made of two half-shells, which are mounted and attached to the main body. The half-shells are joined at a horizontal level at a joint plane passing through the pitch setting axis.

[0038] --The cylindrical part is glued to the main body;

[0039] --At least one preloaded assembly ring is mounted around the half-shell to keep the half-shell securely against the body, the preloaded assembly ring extending about the pitch setting axis;

[0040] --The lower preload assembly ring is mounted on the low cylindrical surface of the cylinder and extends around at least a portion of the free end of the body;

[0041] --The upper preload assembly ring is mounted on the high cylindrical surface of the cylinder and extends around a portion of the spherical part of the body;

[0042] --The claw-shaped clutch ring is configured to be mounted on a tall cylindrical surface of the cylindrical portion;

[0043] --The first guide bearing extends at least partially around the lower preload assembly ring, and the second guide bearing extends at least partially around the upper preload assembly ring.

[0044] During operation, the guide bearings withstand the mechanical forces generated by the aerodynamics and centrifugal forces applied to the blades. The lower bearing can be configured to ensure the centrifugal retention of the blades, while the upper bearing can be configured to withstand the bending moments generated by the aerodynamics and centrifugal forces. The distance between the bearings along the pitch setting axis creates sufficient leverage to prevent the blades from rotating at any stage of flight.

[0045] The present invention also relates to an assembly comprising the system described above and a variable pitch propeller blade, the blade comprising blades connected to a root, the root comprising a body housed in an annular cylindrical portion extending about a pitch setting axis of the blade.

[0046] Preferably, the body is solid (i.e., without a recessed hollow portion). Advantageously, the body includes a free end located on the opposite side of the blade, the free end being configured to mate with the control system in a form-fitting manner. Preferably, the cylindrical portion is independent of the control system.

[0047] The present invention also relates to a turbine engine, particularly a turbine engine for an aircraft, the turbine engine comprising at least one system or component as described above.

[0048] Finally, the present invention relates to a method for installing the system as described above:

[0049] a) By shifting the impeller along a direction parallel to the pitch setting axis, the root of the impeller is inserted into the cup-shaped part of the system.

[0050] b) The free end of the root is joined to a recess in the bottom wall of the cup-shaped part to fix the cup-shaped part to the root of the impeller in terms of rotation, and

[0051] c) Engage the retaining ring, which was previously installed or present around the root of the impeller, into the cup-shaped portion, and install the ring in the cup-shaped portion and onto the root of the impeller by means of a double-claw clutch to ensure that the root is axially retained in the cup-shaped portion.

[0052] Advantageously, during step a) and / or step b), the root of the blade is supported on the elastically deformable member and the elastically deformable member is axially compressed. Attached Figure Description

[0053] Other features and advantages will become apparent from the following description of non-limiting embodiments of the present invention, with reference to the accompanying drawings, in which:

[0054] [ Figure 1 ] Figure 1 It is a schematic perspective view of the propeller blades used in aircraft turbine engines;

[0055] [ Figure 2 ] Figure 2 yes Figure 1 A magnified view of a portion of the blades, showing the root of the blades;

[0056] [ Figure 3 ] Figure 3 It has Figure 1 A schematic perspective view of a partial exploded view of the root of the blade;

[0057] [ Figure 4 ] Figure 4 yes Figure 1 A schematic perspective view of the main body of the root of the whorl blades;

[0058] [ Figure 5 ] Figure 5 yes Figure 1 Another schematic axial section view of the root of the impeller and the guide bearing, with the section plane extending along the chord of the impeller blade;

[0059] [ Figure 6 ] Figure 6 yes Figure 1 A schematic axial cross-sectional view of the root of the impeller and the guide bearing, with the cross-sectional plane extending transversely to the chord of the impeller blade.

[0060] [ Figure 7 ] Figure 7 It is along Figure 5 Another schematic cross-sectional view of line VII-VII;

[0061] [ Figure 8 ] Figure 8 yes Figure 1 A schematic axial cross-sectional view of the blade root and the system for controlling the angular pitch of the blade;

[0062] [ Figure 9 ] Figure 9 yes Figure 8 A schematic perspective view of the cup-shaped portion of the system;

[0063] [ Figure 10 ] Figure 10 yes Figure 8 A schematic perspective view of the claw-shaped clutch ring in the system;

[0064] [ Figure 11 ] Figure 11 yes Figure 8 A schematic perspective view of the locking ring component of the system;

[0065] [ Figure 12 ] Figure 12 yes Figure 8 A schematic perspective and partial axial section view of the root of the impeller and the system, showing the first installation step;

[0066] [ Figure 13 ] Figure 13 yes Figure 8 A schematic perspective and partial axial section view of the root of the impeller and the system, and the second installation step is shown;

[0067] [ Figure 14 ] Figure 14 yes Figure 8 A schematic perspective and partial axial section view of the root of the impeller and the system, and the third installation step is shown;

[0068] [ Figure 15 ] Figure 15 yes Figure 8 A schematic perspective and partial axial section view of the root of the impeller and the system, and the fourth installation step is shown;

[0069] [ Figure 16 ] Figure 16 yes Figure 8 A schematic perspective and partial axial section view of the root of the impeller and the system, and the fifth installation step is shown;

[0070] [ Figure 17 ] Figure 17 yes Figure 8 A schematic perspective and partial axial section view of the root of the impeller and the system, showing the sixth installation step, and...

[0071] [ Figure 18 ] Figure 18 It is a schematic perspective view of a retaining ring with double rows of claw-shaped clutch teeth for use in a system for controlling the angular pitch of a wheel blade according to the present invention.

[0072] [ Figures 19a to 19b ] Figure 19a and Figure 19b This is a schematic diagram of the installation kinematics of the double-claw clutch retaining ring;

[0073] [ Figure 20 ] Figure 20 This is a partial schematic diagram of the axial section of a first embodiment of the system according to the present invention;

[0074] [ Figure 21 ] Figure 21 This is a partial schematic diagram of the axial section of a second embodiment of the system according to the present invention;

[0075] [ Figure 22 ] Figure 22 This is a partial schematic diagram of the axial section of the system according to the third embodiment of the present invention. Detailed Implementation

[0076] Figure 1 The image shows the blade 10 of a propeller for an aircraft turbine engine, which may be ducted or non-ducted.

[0077] The whorl 10 includes blades 12 connected to the root 14.

[0078] The blade 12 has an aerodynamic profile and includes an inner arc surface 12a and an outer arc surface 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 during operation.

[0079] The blade 12 has a free upper end (referred to as the tip) and a lower end connected to the root 14.

[0080] In the example shown, the blade 10 is made of composite material by an injection 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 attached and mounted, for example, by gluing.

[0081] The blade 10 here includes a longon 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 (referred to as body 24) extending from the side opposite the tip of the blade 14 to form part of the root 14.

[0082] Preferably, the spar 22 is made of a 3D woven carbon fiber reinforced epoxy organic matrix composite material, with the warp direction primarily radially oriented at the aerodynamic duct height, while the weft direction is primarily oriented along the chord of the blade. However, the spar can also be a mechanically more advantageous component of different organic matrix composite materials (thermopolymers, thermoplastics, or elastomers), reinforced with long fibers (carbon, glass, aramid, polypropylene) in different fiber arrangements (woven, spun, knitted, unidirectional).

[0083] Although not shown, the blade 12 may be hollow or solid and includes an internal cavity filled with a foam or honeycomb filler material. This filler material is mounted around the spar 22 and covered with an organic matrix composite surface to increase the blade's impact resistance.

[0084] The sheath 20 can be made of titanium or titanium alloy, stainless steel, steel, aluminum, nickel, etc. The inner arc surface 12a or even the outer arc surface 12b of the blade 12 can be covered with a polyurethane film to prevent corrosion.

[0085] The root portion 14 basically comprises two parts, namely the body 24 and the annular cylindrical portion 26, which extends around the axis A of the body 24 and the impeller.

[0086] Axis A is the extension axis of blade 10 and blade 12, and in particular the pitch setting axis of the blade (i.e., the axis around which the angular position of the blade is adjusted). Axis A is also generally a radial axis, and therefore extends radially along the axis of rotation of the propeller equipped with the blade.

[0087] exist Figures 3 to 7The specific shape of the main body 24 of the root 14 can be clearly seen in the middle.

[0088] The main body 24 basically consists of three parts:

[0089] - Free end 28, which is located on the opposite side of blade 12.

[0090] - Support 30, which is located on one side of the blade, and

[0091] -Spherical portion 32, which is located between the free end and the support.

[0092] 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 axis A to achieve detrompage or indexing, as will be explained in more detail below.

[0093] Pb is defined as a transverse plane, that is, a plane perpendicular to axis A that passes substantially through the middle of end 28 and is measured along axis A. This plane Pb is referred to as the low 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 low section) has a value or surface area (e.g., the maximum value, denoted as Sb) and has a generally rectangular shape in the example shown.

[0094] As will be described below, end portion 28 is configured to cooperate with pitch control system 34 for the blades.

[0095] Column 30 has a relatively complex shape and can be considered to include:

[0096] - Two lateral surfaces 30a and 30b are located on one side of the inner arc surface 12a and the outer arc surface 12b of the blade 12, respectively. These two lateral surfaces converge toward each other along axis A and in the direction of the tip of the blade 12 (see...). Figure 4 and Figure 6 ),as well as

[0097] - Two edges, namely upstream edge 30c and downstream edge 30d, which are separated from each other along axis A and along the tip of blade 12 (see...). Figure 4 and Figure 5 ).

[0098] Ph is defined as a transverse plane passing through the support column 30, specifically a transverse plane passing through the lower end of the support column. This plane Ph is referred to as the high plane or upper plane. In this plane, the cross-section of the support column can have a non-circular shape (e.g., oval, elliptical, square, or rectangular). This cross-section (referred to as the high section) has a value or surface area (e.g., the maximum value, denoted as Sh).

[0099] The spherical portion 32 has a generally convex or dome-shaped shape, which extends about axis A.

[0100] Pm is defined as the intermediate plane passing through the spherical portion 32, specifically the intermediate plane passing through the largest cross-sectional portion of the spherical portion (denoted as Sm). This plane Pm is referred to as the average plane. In this plane, the cross-section of the spherical portion 32 may have a circular shape, although this cross-section is not restrictive.

[0101] It should be understood that plane Pm lies between planes Pb and Ph. The cross-section of the spherical portion 32 decreases from plane Pm (Sm) to plane Ph, and decreases from plane Pm to plane Pb. Therefore, it can be understood that Sm is greater than Sb and Sh. Furthermore, in the example shown, Sh is greater than Sb.

[0102] As in Figure 3 As can be seen, the cylindrical portion 26 is made of two half-shells 26a and 26b, which are mounted and attached to the main body 24. For example, one half-shell is on one side of the inner arc surface 12a of the blade, and the other half-shell is on one side of the outer arc surface 12b of the blade 12. Thus, the half-shells 26a and 26b are joined at the level of the joining plane, which passes through the axis A and extends substantially parallel to the chord of the blade 12.

[0103] Advantageously, the cylindrical portion 26 is preferably attached to the body 24 by adhesive bonding. The adhesive extends between the cylindrical portion and the body around axis A.

[0104] The barrel portion 26 is preferably made of metal (steel, titanium, or a titanium alloy such as TA6V). The adhesive is, for example, an epoxy adhesive filled with thermoplastic or elastomer nodules or reinforced with fabric. This bonding method is particularly suitable because the contact surface area between the cavity of the barrel portion and the body, which may be a composite material, is large. The presence of adhesive bonding is advantageous because it allows for the correction of minor shape defects. Adhesive bonding also allows for the prevention of friction at the metal / composite material interface, thereby increasing the service life of the impeller.

[0105] Several possibilities are envisioned for mounting the cylinder 26 to the body 24. The first possibility is that once the two half-shells 26a, 26b of the cylinder 26 are installed, a gap is intentionally left between them to allow for proper pressure application during adhesive bonding and curing. The curing stage can be completed in an autoclave, with the entire impeller inside a vacuum bag. However, this operation can also be performed in a flattening machine. However, a disadvantage of leaving a gap between the two half-shells 26a, 26b is that the positioning of the two half-shells is more difficult to control, thus requiring rework of the outer surfaces. The second possibility is to mount one half-shell against the other around the body 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 the machining operation to ensure the geometry of the outer surfaces once the half-shells are reassembled. This allows for control over the positioning and geometry of the outer surfaces of the cylinder 26 without requiring additional machining after bonding. In any case, locating pins or stops can be considered to ensure the relative position of the cylindrical half-shell.

[0106] However, the presence of glued joint between the body and the cylinder is not mandatory, although it is highly advantageous. Alternatively, prestressed washers (or springs) can be used between the cylinder and the composite body to radially push the body against the support surface of the cylinder. When the two halves of the cylinder are mounted around the spherical portion, the geometry of the cylinder can also be used to slightly “clamp” the body. In this case, it is the deformation of the cylinder that generates the prestress. Therefore, tools must be provided to hold this position before final assembly.

[0107] As in Figure 5 and Figure 6 As can be seen, the cylindrical portion 26 covers and conforms to at least a portion of the spherical portion 32 and at least a portion of the support 30. The cylindrical portion 26 has a cross-sectional shape that is complementary to the spherical portion 32 at the level of the intermediate cross-section Sm, and a cross-sectional shape that is complementary to the support 30 at the level of the high cross-section Sh.

[0108] More specifically, in the example shown, the cylindrical portion 26 comprises three parts.

[0109] -Lower end portion 36, which has a generally annular shape (see...) Figures 5 to 7 The lower end extends at the level of the free end 28 of the root and extends around the free end of the root.

[0110] - Upper end portion 38, which extends horizontally at the plane Ph and includes two lateral lips 40 applied to the sides 30a, 30b of the support 30, and

[0111] - The middle portion 42 is applied to the spherical portion 32 and closely conforms to the shape of the spherical portion.

[0112] The lip 40 is supported on the sides 30a and 30b of the support column 30, which allows the root 14 of the blade to be hardened and strengthens the resistance of the root of the blade to torsion around the pitch setting axis A.

[0113] Furthermore, the lips allow for energy absorption in the event of an impact to the impeller 10 (such as from a bird ingestion). Rounded corners may be present on these lips to prevent localized wear or damage to the main body.

[0114] The inner surface of the cylindrical portion 26 that contacts the body 24 serves as a support surface. Compared to a broached attachment, the support surface is maximized by utilizing the entire circumference of the blade's base. In a broached attachment, only two distinct surfaces at the blade root, located on the inner and outer arc surfaces respectively, are supported on the support surface, while the surfaces at the blade root located on the leading and trailing edges are free. Also compared to a broached attachment, the support surface has a much greater radial height, which contributes to a significant increase in its surface area. This large support surface allows for reduced contact pressure under all operating conditions.

[0115] The cylindrical portion 26 includes two cylindrical surfaces 44 and 46a for mounting preload assembly rings 48 and 50. The preload assembly rings 48 and 50 enable the half-shells 26a and 26b to be held fastened to each other and to the main body 24. The preload assembly rings 48 and 50 extend about axis A.

[0116] Surface 44 is located on the lower end 36 and is oriented radially outward relative to axis A. This surface is fitted with a pre-tightened receiving ring 48, which engages from below and is axially supported on a cylindrical support surface located at the junction of the end 36 and the intermediate portion 42 of the cylindrical portion 26.

[0117] Surface 46a is located on the intermediate portion 42 and is oriented radially outward relative to axis A. This surface is fitted with a pre-tightened receiving ring 50, which engages from above and is axially supported on a cylindrical support surface located near plane Pm.

[0118] As can be seen, surface 46a is located adjacent to cylindrical surface 46b, which is designed to receive retaining ring 52, as will be described below.

[0119] In the example shown, surfaces 44 and 46a and rings 48 and 50 have different diameters. The diameter of surface 46a is larger than the diameter of surface 44, therefore the diameter of ring 50 is larger than the diameter of ring 48.

[0120] Surfaces 46a and 46b may have the same or different diameters. For example, the diameter of surface 46b may be slightly smaller than the diameter of surface 46a. This is especially true when ring 50 is to be mounted relative to surface 46b with a predetermined radial clearance.

[0121] from Figure 5 and Figure 6 As can be seen, ring 50 is located between plane Ph and plane Pm, and ring 48 is located between plane Pm and plane Ps.

[0122] 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 about axis A and root 14.

[0123] There are two bearings 54 and 56 here, namely the lower bearing 54 and the upper bearing 56.

[0124] 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.

[0125] Bearing 54 extends substantially between plane Pm and plane Pb, and thus extends around the lower portion of ball 32. The bearing also extends around ring 48. The diameter of bearing 54 is smaller than the diameter of bearing 56, and the diameter of the balls in bearing 54 is larger than the diameter of the balls in bearing 56.

[0126] Bearing 54 is also an angular contact bearing. In the example shown, the bearing support point or surface of the ball on the raceway of the ball rings 54a, 54b is located on a truncated conical surface S1 that extends along axis A, and the maximum diameter of the truncated conical surface is located on one side of the tip of the impeller.

[0127] Bearing 56 extends substantially between planes Pm and Ph, and thus extends around the upper portion of spherical portion 32. The bearing also extends around ring 50. Bearing 56 is also in angular contact. In the example shown, the bearing support points or surfaces on the raceways of the ball rings 56a, 56b are located on a truncated conical surface S2, which extends along axis A, and the maximum diameter of this truncated conical surface is located on one side of the free end of the root of the impeller.

[0128] The intermediate section, located between the two bearings 54 and 56, is highly advantageous in terms of overall radial dimensions because a portion of the support surface height between the intermediate and high sections lies within the cup-shaped portion 58, unlike the broached attachments integrated into the pivot in the prior art. This helps reduce the overall radial dimensions of the control system 34.

[0129] Figures 8 to 17 Examples of embodiments of the system are shown, and in particular examples of embodiments of the retaining ring 52 are shown.

[0130] System 34 includes a cup-shaped portion 58, which includes an annular wall 58a extending around axis A. The wall 58a includes a lower axial end enclosed by a bottom wall 58b and an open upper axial end, the upper axial end being configured such that the root 14 of the impeller can be mounted within the cup-shaped portion.

[0131] 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-shaped portion is fixed to the root in terms of rotation about the axis.

[0132] In this context, it should be understood that the bottom wall 58b includes a recess 60 having a non-circular cross-section, particularly a 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 eccentric relative to axis A in a manner similar to that of end portion 28 (see [reference]). Figure 7 When the root is inserted and installed into the cup-shaped portion 58, this eccentricity enables indexing and error prevention, while the end 28 has only one possible engagement position in the recess 60.

[0133] The recess 60 is located on the upper or inner surface of the bottom wall 58b of the cup-shaped portion 58, so that the recess is located inside the cup-shaped portion and is oriented toward the root.

[0134] System 34 generates torque at the blade root that counteracts the torsional moment generated by aerodynamics and centrifugal force. Like the rest of the body 24 of the root 14, the end 28 of the root 14 can be enclosed in the cylindrical portion 26. In this case, the end of the root will also have a non-circular shape to constrain rotation of that end. However, it is advantageous, as described above, to have this end of the body protrude from the cylindrical portion to directly constrain rotation of the body. This provides a more direct force path, with the torsional moment applied directly to the body. The dimensions of the low section are strictly smaller than the maximum dimensions of the intermediate section to limit the overall circumferential dimension at that height. Therefore, the overall circumferential dimension of the cylindrical portion at this height is also smaller than the overall circumferential dimension at the level of the intermediate section. This allows for a reduction in the diameter of the lower bearing located below the intermediate section. Therefore, the blade root can be integrated radially downwards, which significantly reduces the theoretical hub ratio associated with root integration. Those skilled in the art know that a low hub ratio improves engine performance, particularly resulting in a more compact and therefore lighter engine. This last point is a very important advantage of this technical solution compared to competitors, who have traditionally proposed cylindrical sections with a cylindrical external shape.

[0135] The bottom wall 58b includes a lower or outer surface located on the opposite side of the root 14 and includes a cylindrical extension 62 extending along axis A and including an external thread or external straight spline 64 for rotatably connecting the system to a pitch changing mechanism (not shown), which is common to the propeller blades 10 and the different systems 34.

[0136] An elastically deformable member 66 (such as a helical spring) extends about axis A and is mounted within the cup-shaped portion 58. The member 66 is axially supported on 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 of the blade toward the outside of the cup-shaped portion, i.e., axially biased toward the tip of the blade.

[0137] Component 66 is supported on the cylindrical support surface 68 of the cylindrical portion 26. In the example shown, component 66 is centered by engaging the upper end of the component to and around the cylindrical edge 70 of the cylindrical portion, and by engaging the lower end of the component to and around the cylindrical edge 72 of the cup-shaped portion, which is located at the outer periphery of the bottom wall 58b.

[0138] Component 66 extends here around the pre-tightening assembly ring 48.

[0139] As in Figure 8 As can be seen, the cup-shaped portion 58 is designed to support bearings 54 and 56, which ensure that the cup-shaped portion is centered and guided about axis A relative to the housing 74 or the fixed structure of the turbine engine.

[0140] Bearings 54 and 56 may be part of a control system. In particular, at least one of the guide bearings may have an inner ring integrated into the cup-shaped portion.

[0141] The same applies to the lower bearing 54, which has an inner ring 54a integrated into the cup-shaped portion 58. In effect, this means that the cup-shaped portion includes a raceway 54aa at 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 cup-shaped portion and the lower end of the wall 58a. The outer ring 54b of the bearing 54 is attached to the housing 74, for example, by preload assembly. Furthermore, advantageously, the cup-shaped portion 58 is designed to apply prestress to the bearing 54.

[0142] The outer ring 56b of the bearing 56 is attached to the housing 74, for example, by preload assembly. The inner ring 56a of the bearing engages with the free upper end of the cup-shaped portion 58 and the free upper end of the wall 58a, and engages around the free upper end of the cup-shaped portion and the free upper end of the wall. This end of the wall 58a includes an outer cylindrical surface 76 for mounting the inner ring 56a and external threads for tightening 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-shaped portion 58.

[0143] The cup-shaped portion wall 58a also includes a device configured to cooperate with the aforementioned retaining ring 52 at its inner periphery.

[0144] The retaining ring 52 extends about axis A and is configured to be mounted around the root 14. The retaining ring 52 is configured to be mounted inside the cup-shaped portion and to engage with the annular wall 58a of the root 14 and the cup-shaped portion 58, respectively, to ensure that the root is axially retained in the cup-shaped portion.

[0145] exist Figures 8 to 17 In an exemplary embodiment, the retaining ring 52 is a claw-shaped clutch ring, which includes an outer claw-shaped tooth 84 configured to engage with the complementary inner claw-shaped tooth 82 of the annular wall 58a of the cup-shaped portion 58.

[0146] exist Figure 9 The teeth 82 of the cup-shaped portion 58 can be clearly seen. These teeth are evenly spaced around axis A. In the non-limiting example shown, there are six teeth. For example, each of these teeth extends at an angle between approximately 20° and 30° around axis A.

[0147] Each tooth in tooth 82 includes a groove 86 at its inner periphery, the groove being circumferentially oriented relative to axis A. The groove 86 of tooth 82 forms a discontinuous valley around axis A.

[0148] exist Figure 10 The claw-shaped clutch ring can be clearly seen. The teeth 84 of the claw-shaped clutch ring are regularly spaced around axis A. In the non-limiting example shown, there are six teeth. For example, each of these teeth extends at an angle between approximately 20° and 30° around axis A.

[0149] Tooth 84 is complementary to tooth 82 and is configured to engage with these teeth via a claw clutch. The installation method of the claw clutch is well-known in the aerospace field; the claw clutch will be... Figures 12 to 17 This demonstrates the installation method.

[0150] The ring 52 includes an inner cylindrical surface 52a, which is designed to engage with the aforementioned surface 76 of the cup-shaped portion 58 by sliding.

[0151] Ring 52 includes a second set of teeth 88 that extend axially upward on one side of the tip of blade 10. These teeth 88 are also regularly spaced around axis A. In the example shown, there are six teeth 88. These teeth can 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 extends at an angle between approximately 10° and 20° around axis A.

[0152] Each tooth in tooth 88 includes a groove 90 at its inner periphery, which is circumferentially oriented relative to axis A. The groove 90 of tooth 88 forms a discontinuous valley around axis A.

[0153] Figure 11 A locking ring 92 is shown, which is configured to engage axially between claw teeth 82, 84 to prevent rotation of ring 52 within cup portion 58.

[0154] The annular component 92 includes slides 94 (in the non-limiting example shown, the number of slides is six), which are designed to engage in the interdental spaces extending between the teeth 82 and 84. Therefore, it should be understood that these slides 94 have shapes complementary to the shapes of these spaces and are regularly spaced around axis A.

[0155] In the example shown, slides 94 are secured to each other by bridging members 96 extending circumferentially between slides 94. There are five bridging members 96, each extending between two adjacent slides 94. Two slides in the slides 94 are intentionally not connected by bridging members, leaving the annular member 92 open. This simplifies assembly when the annular member is installed in system 34 by moving the slides away from or toward each other.

[0156] Each slide in slide 94 includes a groove 98 at its inner periphery, which is circumferentially oriented relative to axis A. The groove 98 in slide 94 forms a discontinuous valley around axis A.

[0157] The system also includes a ring retainer 100, which is only used when... Figure 17 As can be seen in the text.

[0158] A retaining ring 100 is installed in the cup-shaped portion 58 to axially retain the locking annular member 92 within the cup-shaped portion 58. The retaining ring 100 can also be separated or opened to facilitate its installation, and when the grooves 86, 98 are all located in the same plane perpendicular to axis A and arranged circumferentially relative to each other to form a complete valley around axis A, the retaining ring is intended to engage in the groove 86 of the tooth 82 of the cup-shaped portion and the groove 98 of the slide 94 of the annular member 92 (see [link to relevant documentation]). Figure 16 and Figure 17 ).

[0159] Now refer to Figures 12 to 17 , Figures 12 to 17 The following diagram shows the installation method using the method provided by [the manufacturer / organization]. Figure 1 The blade 10 shown and Figure 8 The method for forming components of system 34 shown.

[0160] exist Figure 12 In the first step shown, the root 14 of the impeller 10 is engaged in the cup-shaped portion 58 of the system 34 by axial translation along axis A until the end 28 of the root body 24 is engaged in the recess 60 of the cup-shaped portion 58. As can be seen in the figure, the ring 52 has been forcibly installed around the support 30 of the root body. Although not shown in the figure, when the root 14 is inserted into the cup-shaped portion 58, the member 66 ( Figure 8 () is compressed.

[0161] exist Figure 12 and Figure 13 In the second step shown, the ring 52 is positioned at an angle around axis A, such that the teeth 84 of the ring are aligned with the space between the teeth 82 located in the cup-shaped portion. Then, the ring 52 is axially translated within the cup-shaped portion 58 until the ring 52 engages on the surface 46b of the cylindrical portion 26, and the teeth 84 are positioned directly below the teeth 82, as shown. Figure 13 As shown. The groove 90 provided on the teeth can be used to clamp the ring 52 with a suitable tool.

[0162] exist Figure 13 and Figure 14 In the third step shown, ring 52 is rotated about axis A, such that the teeth 82, 84 are axially aligned with each other. This angular displacement is approximately 25° to 30° due to the angular extension of the teeth in the example shown. Teeth 88 can be used to clamp ring 52 and rotate it using the aforementioned tool. Member 66 (not shown) axially offsets the root from the cup-shaped portion outwards, such that teeth 84 are axially supported on teeth 82. Thus, the root is axially held within the cup-shaped portion and system 34. During operation, centrifugal forces applied to the impeller are transmitted to the cup-shaped portion 58 via teeth 82, 84, and these forces are directly borne by bearing 54, whose inner ring 54a is integrated into the cup-shaped portion 58.

[0163] exist Figure 15 and Figure 16In the fourth step shown, the annular member 92 is positioned at an angle about axis A such that the slide 94 of the annular member is aligned with the space between the teeth 82, 84. Then, the annular member 92 is axially translated within the cup-shaped portion 58 until the slide 94 engages in these spaces. The bridging member 96 can then be supported on the teeth 84 of the ring 52. Therefore, the annular member 92 prevents any rotation of the ring 52 within the cup-shaped portion 58.

[0164] exist Figure 17 In the final step shown, the retaining ring 100 engages in the circumferentially aligned grooves 86 and 98. The retaining ring 100 prevents accidental disassembly of the annular member 92.

[0165] It should be understood that the blade removal is performed by reversing the aforementioned steps. It should also be understood that one of the basic steps in the installation and removal of the root 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 can be removed from the propeller by removing and discarding a minimal number of components.

[0166] Now refer to Figure 18 , Figure 18 An example of an embodiment of a double-claw clutch ring 152 for a control system 34 according to the present invention is shown.

[0167] Ring 152 includes an annular body with an inner cylindrical surface 152a at its inner periphery and two annular rows of outer claw-shaped clutch teeth (labeled 154 and 156) at its outer periphery.

[0168] The teeth 154 are located at the upper end of the ring 152. These teeth are intended to be located on one side of the blade 12 of the impeller 10, in a mounting position around the root 14 of the impeller 10.

[0169] The tooth 156 in this row is located at the lower end of the ring 152.

[0170] The two rows of teeth 154 and 156 are separated from each other by a space E, which has an axial dimension labeled E1. This dimension E1 is measured along the axis of rotation of the ring 152, which coincides with the pitch setting axis A of the impeller 10 in the impeller mounting position.

[0171] The teeth 154 in this row have an axial thickness E2 measured along the axis, and the teeth 156 in this row have an axial thickness E3 measured along the axis.

[0172] Two rows of teeth 154, 156 may extend radially outward from a common outer cylindrical surface 152b relative to axis A. These two rows of teeth 154, 156 then have the same or similar inner diameter Dint. These two rows of teeth 154, 156 may also have the same or similar outer diameter Dext.

[0173] The number of teeth and the range of tooth angles in each row of teeth 154, 156 can be specifically selected according to the required mechanical strength of ring 152.

[0174] The angular position of the teeth in one row relative to the teeth in another row depends on the envisioned mounting type of ring 152.

[0175] Figure 19a The first kinematics of the mounting ring 152 are shown when the two rows of teeth 154 and 156 are axially aligned, as follows: Figure 18 The situation is as shown in the example.

[0176] In this case, the double-claw clutch is executed by a single translation of the ring 152 in the cup-shaped portion 58 and a single rotation of the ring 152 inside the cup-shaped portion 58.

[0177] like Figure 19a The diagram schematically shows that the cup-shaped portion 58 also includes two annular rows of internal teeth 158, 160. For clarity, the diagram only shows two teeth in each row of teeth 158, 160 and one tooth in each row of teeth 154, 156.

[0178] The teeth 158 in this row are located at the upper end of the cup-shaped portion 58 and are designed to engage with the teeth 154 in this row via a claw clutch. The teeth 160 in this row are located directly below the teeth 158 in this row and are designed to engage with the teeth 156 in this row via a claw clutch.

[0179] The two rows of teeth 158, 160 are separated from each other by a space H having an axial dimension H1. This dimension is measured along axis A. This dimension H1 is greater than the thickness E2 of the teeth 154 in this row, so that these teeth can engage between two teeth in the two rows of teeth 158, 160 in the cup-shaped portion.

[0180] Arrow F1 indicates the translational displacement of ring 152 within cup-shaped portion 58 along axis A. The two rows of teeth 154, 156 of ring 152 are aligned with the inter-tooth spaces of the two rows of teeth 158, 160. Displacement is performed until the row of teeth 154 is laterally aligned with space H.

[0181] Arrow F2 indicates the rotational displacement of ring 152 within cup-shaped portion 58 about axis A. Displacement continues until the two rows of teeth 154, 156 are axially aligned with the two rows of teeth 158, 160.

[0182] The following text will refer to Figure 20 and Figure 21 More specifically, one of the rows of teeth 154, 156 is configured such that the axial support G abuts against one of the rows of teeth 158, 160 to ensure that the impeller 10 is axially held within the cup-shaped portion 58. This is the case of the two rows of teeth 154, 158 in the illustrative example shown.

[0183] The other row of teeth in the two rows of teeth 154, 156 is configured to be separated from one row of teeth in the two rows of teeth 158, 160 by a predetermined axial clearance J to ensure the safety of this retention in the event of a failure. This is the case for the two rows of teeth 156, 160 in the illustrative example shown.

[0184] Then, a locking ring 92 or a slide 94 of the type described above can be used to fix the ring 152 in the cup-shaped portion in terms of rotation.

[0185] Figure 19b The second kinematics of the mounting ring 152 is shown when the two rows of teeth 154, 156 are angularly offset and therefore not axially aligned. This example illustrates the case of an angular offset of one pitch, where the step size represents the angular range of the teeth.

[0186] In this case, the double-claw clutch is activated by two translations of the ring 152 within the cup-shaped portion 58 and two rotations of the ring 152 within the cup-shaped portion 58.

[0187] Arrow F1 indicates the translational displacement of ring 152 within cup-shaped portion 58 along axis A. The space between the teeth 156 and 158 of this row of ring teeth is aligned. The displacement continues until the teeth of row 156 are below the teeth of row 158.

[0188] Arrow F2 indicates the rotational displacement of ring 152 within cup-shaped portion 58 about axis A. This displacement continues until the teeth 156 of this row are axially aligned with the inter-tooth space of teeth 160 in this row.

[0189] Arrow F3 indicates the translational displacement of ring 152 within cup-shaped portion 58 along axis A. This displacement continues until the teeth 156 of this row are below the teeth 160 of this row.

[0190] Arrow F4 indicates the rotational displacement of ring 152 within cup-shaped portion 58 about axis A. Displacement continues until teeth 156 of this row are axially aligned with teeth 160 of this row, and teeth 154 of this row are axially aligned with teeth 158 of this row.

[0191] As described above, one row of teeth 154, 156 is configured to abut against one row of teeth 158, 160 along the axial support portion G to ensure axial retention of the impeller within the cup-shaped portion. The other row of teeth 154, 156 is configured to be separated from one row of teeth 158, 160 by a predetermined axial clearance J to ensure the safety of this retention in the event of a failure.

[0192] Then, a locking ring 92 or a slide 94 of the type described above can be used to fix the ring 152 in the cup-shaped portion in terms of rotation.

[0193] Figures 20 to 22 A more specific embodiment of the double-claw clutch ring 152 according to the present invention is shown.

[0194] Each of these rings 152 is used in conjunction with the above, particularly regarding... Figure 8 In environments similar to those described above, the foregoing description applies. Figures 20 to 22 The embodiments are provided that the foregoing description does not contradict the following.

[0195] Reference Figure 20 The upper axial end of the wall 58a of the cup-shaped portion 58 includes two rows of teeth 158, 160 at its inner periphery. The teeth in the two rows of teeth 158, 160 have substantially the same inner and outer diameters. The outer periphery of the upper axial end of the wall 58a includes the external thread of a nut 78, which is supported on the inner ring 56a of the bearing 56.

[0196] In this embodiment, the active teeth in this row are teeth 156, i.e., the lower row of teeth. Teeth 156 are designed to engage with teeth 160 of the cup-shaped portion 58 outwards via the axial support portion G. The passive teeth in this row are teeth 154, i.e., the upper row of teeth. Teeth 154 are separated from teeth 158 by an axial clearance J.

[0197] Ring 152 is axially supported inward on pre-tightened assembly ring 50, and during the ring's double-claw clutch operation, the outer cylindrical surface 152a of the ring slides into contact with cylindrical surface 46a. Here, surface 152a extends only a portion of the axial dimension of ring 152. The axial dimension of surface 152a is approximately 90% to 100% of the maximum axial dimension of the row of teeth 156 or ring 152.

[0198] Figure 20 The embodiment shown represents a relatively simple solution in which the passive claw tooth 154 is not subjected to any specific force unless the active claw tooth 156 fails, and is therefore isolated. However, there is a concern that the force path of the passive claw tooth may also be damaged due to the failure of the active claw tooth, which would reduce the effectiveness of the passive claw tooth.

[0199] exist Figure 21 In this row, the driving teeth are teeth 154, i.e., the upper row of teeth. Teeth 154 are designed to engage with teeth 158 of the cup-shaped portion 58 outwards via the axial support portion G. The driven teeth are teeth 156, i.e., the lower row of teeth. Teeth 156 are separated from teeth 160 by an axial clearance J.

[0200] Ring 152 is axially supported inward on pre-tightened assembly ring 50, and during the ring's double-claw clutch operation, the outer cylindrical surface 152a of the ring slides into contact with cylindrical surface 46a. Here, surface 152a extends over the main portion of the axial dimension of ring 152. The axial dimension of surface 152a is approximately 90% to 100% of the ring's maximum axial dimension.

[0201] Figure 21 The embodiment shown illustrates a compact solution. This solution also has the advantage of better reliability for the passive claw portion, as a failure of the active claw portion is less likely to damage the force path of the passive claw portion.

[0202] exist Figure 22 In the alternative embodiment shown, ring 152 is different Figure 20 and Figure 21 The ring, particularly the inner periphery of the ring, has an inwardly flared truncated cone shape, which is at least partially complementary to the spherical portion at the root. The aforementioned cylindrical portion 26 can then be removed or even considered integrated into the ring 152 (outside the spherical portion).

[0203] Furthermore, ring 152 may be segmented and includes multiple corner segments arranged adjacent to each other around axis A.

[0204] Although loop segment 152 is independent, loop segments can be connected by having Figure 19a and Figure 19b A kinematic double-claw clutch in kinematics is installed separately in the same manner as an integral ring.

[0205] Advantageously, the aforementioned gap J is determined to be the imbalance that occurs when the propeller equipped with system 34 rotates. This imbalance is caused by the radial displacement of the blade 10 after the main claw breaks and can be detected by a suitable sensor mounted on the propeller. Detecting this imbalance can trigger an engine shutdown to limit the impact force during the contact process after the main claw breaks.

[0206] Regardless of the implementation, the size (especially the axial thickness) of the passive claw tooth is smaller than that of the active claw tooth because, unlike the active claw tooth, the passive claw tooth has no fatigue dimension and can withstand higher stress.

[0207] The present invention also proposes a method for installing system 34, the method comprising the following steps:

[0208] a) By shifting the impeller 10 in a direction parallel to the pitch setting axis A, the root 14 of the impeller 10 is inserted into the cup-shaped portion 58 of the system 34.

[0209] b) The free end 28 of the root 14 is engaged in the recess 60 of the bottom wall 58b of the cup-shaped portion 58 to fix the cup-shaped portion 58 to the root 14 of the impeller 10 in terms of rotation, and

[0210] c) Engage the retaining ring 52, which was previously installed or present around the root 14 of the impeller 10, into the cup-shaped portion 58, and install the ring 52 in the cup-shaped portion 58 and onto the root 14 of the impeller 10 by means of a claw clutch, to ensure that the root 14 is axially retained in the cup-shaped portion 58. As described above, depending on the type of double claw clutch, the following is employed... Figure 19a or Figure 19b The kinematics of the ring. Therefore, in step c), the ring 152 engages in the cup-shaped portion 58 and engages on the root 14 of the impeller 10, thereby ensuring, in particular, that the root 14 is axially retained in the cup-shaped portion 58 by taking into account the segments of the ring 152. An insertion notch may be provided in the cup-shaped portion 58 to facilitate the installation of the ring, and where appropriate, the segments of the ring or the geometry of the segments may be adapted to allow installation without any insertion notch.

[0211] Other variant embodiments, not shown, are possible and include:

[0212] • The semi-shells 26a and 26b of the cylindrical part 26 can be installed onto the main body 24 by bolting, riveting, welding, etc.

[0213] The adhesive used to connect the cylindrical portion 26 to the main body 24 can be an epoxy adhesive, but it can also be an elastomer or thermoplastic adhesive. A non-stick film can also be used to allow for relative movement while limiting wear caused by friction.

[0214] • The issue remains about the tube / body interface. Among the proposed technical solutions (gluing, applying prestress through washers or springs, applying prestress through the geometry of the tube), it is also possible to combine multiple technical solutions that can be combined independently of the presence of a gap between the two parts of the tube.

[0215] • Although not very advantageous, the radial position of the bearing that ensures the centrifugal retention of the blades can be opposite to the radial position of the bearing that bears the bending moment generated by aerodynamics and centrifugal force.

Claims

1. A system (34) for controlling the pitch of a propeller blade (10) of an aircraft turbine engine, characterized in that, The system includes: - A cup-shaped portion (58) comprising an annular wall (58a) extending about an axis (A) intended to set the pitch of the propeller blades, the annular wall (58a) comprising a lower axial end enclosed by a bottom wall (58b) and an open upper axial end, the upper axial end being configured such that the root (14) of the propeller blades (10) can be mounted inside the cup-shaped portion (58), the bottom wall (58b) being configured to mate in a form-fitting manner with the free end (28) of the root (14), such that the cup-shaped portion (58) is rotationally secured to the root (14) about the axis (A), and - A retaining ring (152) extending about the axis (A) and configured to be mounted around the root (14), the retaining ring (152) being configured to be mounted within the cup-shaped portion (58) and engaging with the annular wall (58a) of both the root (14) and the cup-shaped portion (58) to ensure axial retention of the root (14) within the cup-shaped portion (58). Furthermore, the retaining ring (152) is a ring with a double claw clutch, the ring having a double claw clutch comprising two annular rows of outer claw teeth (154, 156), the outer claw teeth of the first row of these rows of outer claw teeth being configured to engage with the first inner claw teeth of the annular wall (58a) of the cup-shaped portion (58) via a claw clutch, and to engage with these first inner claw teeth via an axial support portion (G), the outer claw teeth of the first row being complementary to the first inner claw teeth to ensure the retention of the root (14) in the cup-shaped portion (58), the outer claw teeth of the second row of these rows of outer claw teeth being configured to engage with the second inner claw teeth of the annular wall (58a) of the cup-shaped portion (58) via a claw clutch, and to be spaced apart from these second inner claw teeth by an axial clearance (J), the outer claw teeth of the second row being complementary to the second inner claw teeth to ensure safety in the event of a failure of the outer claw teeth of the first row.

2. The system (34) according to claim 1, wherein, The first row of outer claw teeth is the upper row of outer claw teeth, which is intended to be located on one side of the blade (12) of the propeller blade (10), and the second row of outer claw teeth is the lower row of outer claw teeth.

3. The system (34) according to claim 1, wherein, The second row of outer claw-shaped teeth is the upper row of outer claw-shaped teeth, which is intended to be located on one side of the propeller blade, and the first row of outer claw-shaped teeth is the lower row of outer claw-shaped teeth.

4. The system (34) according to any one of claims 1 to 3, wherein, The first row of outer claw teeth and the second row of outer claw teeth are axially spaced apart from each other by a space (E) designed to accommodate the first inner claw teeth or the second inner claw teeth, and the axial dimension (E1) of the space is greater than the axial thickness of those inner claw teeth.

5. The system (34) according to any one of claims 1 to 3, wherein, The axial thickness (E2, E3) of the outer claw teeth in the first row is greater than the axial thickness of the outer claw teeth in the second row.

6. The system (34) according to any one of claims 1 to 3, wherein, The first row of external claw teeth and the second row of external claw teeth have substantially the same inner diameter (Dint) and the same outer diameter (Dext).

7. The system (34) according to any one of claims 1 to 3, wherein, The retaining ring (152) includes an inner cylindrical surface (152a) at its inner periphery, which is configured to engage with the root (14) of the propeller blade (10) or the outer cylindrical surface (46a) of an element mounted to the root during the double-claw clutch by sliding. The inner cylindrical surface is complementary to the outer cylindrical surface and is located within the outer claw teeth of the first row or the second row.

8. The system (34) according to claim 7, wherein, The axial dimension of the inner cylindrical surface (152a) is between 90% and 100% of the axial thickness (E2, E3) of the outer claw teeth in the first row or the maximum axial thickness of the fixing ring.

9. The system (34) according to any one of claims 1 to 3, wherein, The system also includes: - A lower rolling guide bearing (54) extends about the axis (A) and is mounted around the lower portion of the annular wall (58a). - An upper rolling guide bearing (56) extends about the axis (A) and is mounted around the upper portion of the annular wall (58a).

10. The system (34) according to claim 9, wherein, At least one of the lower rolling guide bearing (54) and the upper rolling guide bearing (56) has an inner ring integrated into the cup-shaped portion (58).

11. The system (34) according to claim 9, wherein, The upper rolling guide bearing (56) is mounted around the upper portion of the annular wall (58a), the upper portion of the annular wall including the first inner claw teeth and the second inner claw teeth at the inner periphery of the upper portion, and including threads at the outer periphery of the upper portion, to which a nut (78) is screwed and axially supported on the outer ring of the upper rolling guide bearing (56).

12. The system (34) according to any one of claims 1 to 3, wherein, The system further includes a locking ring (92) and an annular retainer (100), the locking ring (92) being configured to engage axially between a third inner claw tooth (82) and a third outer claw tooth (84) to prevent rotation of the ring with a double claw clutch within the cup-shaped portion (58), the annular retainer (100) being mounted in the cup-shaped portion (58) to axially block the locking ring (92) within the cup-shaped portion (58).

13. An assembly comprising a system (34) according to any one of claims 1 to 12 and a variable pitch propeller blade (10), the propeller blade (10) comprising a blade (12) connected to a root (14), the root (14) comprising a body (24) housed in an annular cylindrical portion (26) extending about the axis (A) of the propeller blade, the axis being a pitch setting axis.

14. A turbine engine comprising at least one system (34) according to any one of claims 1 to 12 or a component according to claim 13.

15. The turbine engine according to claim 14, wherein the turbine engine is a turbine engine for an aircraft.

16. A method for installing the system (34) according to any one of claims 1 to 12, wherein, The method includes the following steps: a) By shifting the propeller blade (10) in a direction parallel to the axis (A), the root (14) of the propeller blade (10) is inserted into the cup-shaped portion (58) of the system (34), where the axis is the pitch setting axis. b) Engage the free end (28) of the root (14) into the recess (60) of the bottom wall (58b) of the cup-shaped portion (58) to fix the cup-shaped portion (58) to the root (14) of the propeller blade (10) in rotation, and c) Engage the retaining ring (152) previously mounted or present around the root (14) of the propeller blade (10) in the cup-shaped portion (58), and mount the retaining ring (152) in the cup-shaped portion (58) and on the root (14) of the propeller blade (10) by means of the double claw clutch, to ensure that the root (14) is axially held in the cup-shaped portion (58).

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