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

Abstract

A system (34) for controlling the pitch setting of a propeller blade (10) of an aircraft turbine engine is disclosed, the system (34) being characterized in that the system includes: - a blade (10) including blades (12) connected to a root (14); - a hub (36) intended to accommodate the root (14) of the blade (10); - a ring (38) mounted around the root (14) and in the hub (36); - a support (40, 40') mounted around the root (14) and in the hub (36); and - a nut (42) screwed onto the thread (78) of the ring (38) and configured to axially support against the hub (36) to secure the assembly.

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 aerodynamics 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. Increasing the BPR occurs simultaneously with decreasing the fan pressure ratio (FPR). Therefore, pitch-changing systems (variable-pitch blades) are typically required to make the propeller operable throughout its flight domain.

[0006] There are various techniques for attaching variable pitch propeller blades and for controlling the pitch setting of such propeller blades. However, these techniques are relatively complex and expensive. Furthermore, in the event of blade problems, particularly damage, especially when the propeller is not ducted, 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 propeller blade retaining mechanism, ensuring the blade is held in place to prevent it from being ejected outwards and from impacting the fuselage of the turbine-powered aircraft is of paramount importance. This safety feature, known as "failsafe," is not always present in current technology control systems. Control systems that include this feature typically comprise components that are themselves easily separable and capable of impacting the aircraft's fuselage. The larger and denser these components are, the greater the risk of fuselage damage and the greater the need for specialized protective shields, which can affect the aircraft's mass and, consequently, 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 setting of propeller blades in an aircraft turbine engine, characterized in that the system comprises:

[0010] - A vane, comprising blades connected to a root, the vane including a pitch axis, the root including a spherical portion having two supporting surfaces, a lower supporting surface and an upper supporting surface, extending about the axis.

[0011] A hub comprising an annular wall extending about the axis, the annular wall including a lower axial end closed 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 hub. The bottom wall includes a recess having a non-circular cross-section and being configured to receive a free end complementary in shape to the root, such that the hub is rotatably secured to the root about the axis.

[0012] A ring extending about the axis and mounted around the root and in the hub, the ring including a lower wall located in the hub and including an orifice through which the free end of the root passes, the lower support surface of the spherical portion of the root being configured to be supported on the lower wall at least in the axial direction, supported on the side opposite the blade of the impeller, the ring also including a perforated intermediate wall and threads located at the upper end.

[0013] - Supports, arranged around the axis, and mounted around the root and in the hub, these supports engaging in openings in the intermediate wall and engaging in at least one receiving portion in the annular wall of the hub, the upper support surface of the spherical portion of the root being configured to support these supports at least in the axial direction, supporting the blade side of the impeller, and

[0014] - A nut, which is screwed onto the thread of the ring and configured to be axially supported on the hub, such that tightening the nut supports the lower wall of the ring on the lower support surface of the spherical portion at the root, supports the upper support surface of the spherical portion on the supports, and supports the supports on the complementary support surfaces of the at least one receiving portion of the hub.

[0015] In the pitch system described in this invention, the root of the blade is mounted in a hub, which is configured to rotate about a pitch axis and drive the blade in this motion. To achieve this, the root of the blade is rotatably fixed to the hub, thereby forming a pivotal connection of the blade.

[0016] The pitch setting system includes a ring, supports, and a nut, and this assembly enables multiple functions. The pitch setting system allows the blade root to be assembled to or removed from the hub without disassembling the hub. This assembly and disassembly can be performed externally, which, in the case of a ductless propeller, allows the blade to be removed and taken off without removing the turbine engine (e.g., the turbine engine can still be attached to the aircraft's wing). The supports provide fail-safe functionality. For example, if one of these supports cracks or breaks, the other supports will hold the blade root in place until the damaged support is replaced. Tightening the nut also allows a radial preload to be applied to the blade root, ensuring the blade is secured and held. This preload is advantageously predetermined such that it is not entirely compensated for by forces caused by centrifugal forces, aerodynamics, and torques applied to the blade during propeller operation and rotation.

[0017] The system according to the invention may include one or more of the following features, either individually or in combination:

[0018] - The number of supports is less than or equal to the number of openings in the middle wall of the ring, and each support is engaged in one of these openings;

[0019] - The number of supports is between 5 and 20, preferably between 7 and 11;

[0020] - The lower wall of the ring is a generally truncated conical shape that gradually expands toward the blade, such that the support surface of the lower support surface of the spherical part at the root has an axial component and a radial component relative to the axis at each point.

[0021] - Each of the supports includes a support surface on the upper support surface of the spherical portion at the root, the support surface being shaped such that the support has an axial component and a radial component relative to the axis at any point;

[0022] - The nut is tightened to the outside of the ring and / or axially supported on the upper free end of the hub;

[0023] - Each of the supports includes at least one finger that projects radially outward relative to the axis, and the at least one finger includes an upper surface that is axially supported on a corresponding support surface of the at least one receiving portion;

[0024] - The at least one finger portion further includes a lateral surface that is radially outwardly supported on a corresponding support surface of the at least one receiving portion;

[0025] - Each of the supports includes two fingers that project radially outward relative to the axis and are arranged axially behind the other;

[0026] - The hub includes at least one annular rib extending about the axis and defining at least one receiving portion for engaging the support. The rib includes at least one axial recess configured to allow the supports to be installed one after another.

[0027] - The hub includes two annular ribs, an upper rib and a lower rib, which extend about the axis and define between the two annular ribs at least one receiving portion for engaging the support. The ribs include at least one axial recess configured to allow the supports to be installed one after another.

[0028] The system also includes at least one bolt that engages in one of the openings in the ring and in the at least one recess, the bolt being attached to the ring;

[0029] - Bolts are attached to the ring by one or more screws;

[0030] - The bolt is located on one side of the suction side of the blade, and closer to the trailing edge of the blade than the leading edge of the blade;

[0031] - Before the bolts are installed, the ring is able to rotate about the axis in the hub. After the bolts are installed, the ring is prevented from rotating about the axis by the circumferential abutment of the bolts on the side of the notch.

[0032] --One of the supports forms a bolt;

[0033] --The bolt is independent of the support;

[0034] --The root or the spherical part of the root is solid (i.e., it has no hollowed-out portion);

[0035] --The number of openings in the middle wall of the ring is between 5 and 20, preferably between 8 and 12;

[0036] --The system also includes:

[0037] - A lower rolling guide bearing that extends about the axis and is mounted around the lower portion of the hub;

[0038] - An upper rolling guide bearing extends about the axis and is mounted around the upper portion of the hub;

[0039] --The inner ring of at least one of the guide bearings is integrated into the hub;

[0040] --At least one of the guide bearings is an angular contact bearing;

[0041] --The concave part is eccentric relative to the pitch axis.

[0042] 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 axis creates sufficient leverage to prevent the blades from rotating at any stage of flight.

[0043] The present invention also relates to a turbine engine, particularly an aircraft turbine engine, which includes at least one system as described above.

[0044] Finally, the present invention relates to a method for installing a system as described above, wherein the method includes the following steps:

[0045] a) Insert the ring into the hub.

[0046] b) Insert the root of the impeller into the ring until the lower support surface of the spherical part of the root abuts against the lower wall of the ring.

[0047] c) The support is engaged in the opening in the intermediate wall of the ring and in the at least one receiving portion of the hub, and

[0048] d) Tighten the nut onto the ring and secure it to the hub so that the lower wall of the ring is supported on the lower support surface of the spherical portion at the root, the upper support surface of the spherical portion is supported on the supports, and these supports are supported on the complementary support surfaces of the at least one receiving portion of the hub.

[0049] Advantageously, step c) comprises the following successive sub-steps:

[0050] c1) By axially translating one of the supports through a notch in the hub, one of the supports is engaged in an opening in the opening in the intermediate wall of the ring.

[0051] c2) This causes the ring and support to rotate about the axis inside the hub.

[0052] c3) By axially translating another support through a notch in the hub, the other support is engaged in one of the openings in the intermediate wall of the ring.

[0053] c4) This causes the ring and these supports to rotate about the axis inside the hub.

[0054] c5) For the remaining supports, repeat steps c3) and c4).

[0055] c6) By axially translating the bolt through a notch in the hub, the bolt is engaged in the final free opening in the intermediate wall of the ring, and

[0056] c7) Attach the bolt to the ring.

[0057] In one embodiment, in each of steps c2) and c4), the ring moves by a circumferential pitch equal to 360° / k, where k is the number of openings in the middle wall of the ring. Attached Figure Description

[0058] 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:

[0059] [ Figure 1 ] Figure 1 This is a schematic perspective view of a propeller blade used in an aircraft turbine engine.

[0060] [ Figure 2 ] Figure 2 yes Figure 1 A magnified view of a portion of the blades, showing the root of the blades.

[0061] [ Figure 3 ] Figure 3 This is a schematic axial cross-sectional view of the system according to the invention for setting the angular pitch of a turbine engine propeller blade, according to a first embodiment of the invention.

[0062] [ Figure 3a ] Figure 3a yes Figure 3 A larger proportion of the detailed view,

[0063] [ Figure 4 ] Figure 4 Viewed from above Figure 3 A schematic diagram of the hub of the system.

[0064] [ Figure 5 ] Figure 5 yes Figure 3 A schematic perspective view of the hub of the system shown.

[0065] [ Figure 6 ] Figure 6 yes Figure 3 A schematic perspective view of the rings in the system shown.

[0066] [ Figure 7 ] Figure 7 Viewed from above Figure 3 A schematic perspective view of the support for the system shown.

[0067] [ Figure 8 ] Figure 8 Viewed from above Figure 3 A schematic perspective view of the bolts in the system shown.

[0068] [ Figure 9 ] Figure 9 Viewed from above Figure 3 A schematic diagram of the hub of the system and the ring assembled in the hub is shown, along with the steps in the assembly method according to the invention.

[0069] [ Figure 10 ] Figure 10 This is a schematic diagram of the hub, ring, and support as seen from above, and it also illustrates another step in the method.

[0070] [ Figure 11 ] Figure 11 Is with Figure 10 A similar view, and it shows another step in the method.

[0071] [ Figure 12 ] Figure 12 This is a schematic diagram of the hub, ring, and support as seen from above, and it also illustrates another step in the method.

[0072] [ Figure 13 ] Figure 13 This is a schematic diagram of the hub, ring, support, and bolts as seen from above, and it also shows another step in the method.

[0073] [ Figure 14 ] Figure 14 This is a schematic perspective view of the ring, support, and bolts without the hub.

[0074] [ Figure 15 ] Figure 15 yes Figure 13 A schematic cross-sectional view of the component shown.

[0075] [ Figure 16 ] Figure 16 yes Figure 15 A larger proportion of the detailed view,

[0076] [ Figure 17 ] Figure 17 This is a schematic axial cross-sectional view of a system according to the invention for setting the angular pitch of a turbine engine propeller blade according to an alternative embodiment of the invention, and...

[0077] [ Figure 17a ] Figure 17a yes Figure 17 A larger proportion of the detailed view. Detailed Implementation

[0078] Figure 1 The blade 10 of a propeller for an aircraft turbine engine is shown; the propeller may be ducted or non-ducted.

[0079] The whorl 10 includes blades 12 connected to the root 14.

[0080] The blade 12 has an aerodynamic profile and includes a pressure side 12a and a suction side 12b, which are connected by an upstream leading edge 12c and a downstream trailing edge 12d, the terms upstream and downstream referring to the gas flow around the blade during operation.

[0081] The blade 12 has a free upper end (referred to as the top) and a lower end connected to the root 14.

[0082] 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 polymerizes and hardens, the leading edge 12c of the blade is typically reinforced by a metal shield 20, which is mounted and attached, for example, by gluing.

[0083] The blade 10 here includes a longitudinal beam 22, which includes a web forming the blade 12. The portion inserted into the preform 18 before resin injection, and the portion extending from the side opposite the tip of the blade 14 to form part of the root 14 (referred to as body 24).

[0084] Preferably, the longitudinal beam 22 is made of a 3D woven carbon fiber reinforced epoxy organic matrix composite material, wherein, at the aerodynamic veine height, the warp direction is primarily radially oriented, while the weft direction is primarily oriented along the chord of the blade. However, the longitudinal beam 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).

[0085] 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 longitudinal beam 22 and covered with an organic matrix composite skin to increase the blade's impact resistance.

[0086] The shield 20 can be made of titanium or titanium alloy, stainless steel, steel, aluminum, nickel, etc. The pressure side 12a or even the suction side 12b of the blade 12 can be covered with a polyurethane membrane to prevent corrosion.

[0087] A is the elongation axis of the impeller 10 and blade 12, and in particular the pitch axis used to adjust the pitch of the impeller 10, that is, the angular position of the impeller is adjusted about this axis. Axis A is also generally a radial axis, and therefore extends radially along the axis of rotation of the propeller equipped with the impeller.

[0088] exist Figure 3 As can be seen more clearly, the main body 24 of the root 14 has a specific shape.

[0089] The main body 24 basically consists of three parts:

[0090] - Free end 28, which is located on the opposite side of blade 12.

[0091] - Support 30, which is located on one side of blade 12, and

[0092] -Spherical portion 32, which is located between the free end 28 and the support 30.

[0093] In the example shown, the free end 28 has a generally parallelepiped shape. This end 28 is preferably misaligned or offset relative to axis A to achieve detrompage or indexing, as will be explained in more detail below.

[0094] The support column 30 can have a relatively complex shape and can be considered to include:

[0095] - Two lateral sides 30a and 30b, located on the pressure side 12a and suction side 12b of the blade 12 respectively, converge toward each other along axis A and in the direction of the tip of the blade 12.

[0096] - Two edges, namely upstream edge 30c and downstream edge 30d, which are diverged from each other along axis A and toward the tip of blade 12.

[0097] The spherical portion 32 has a generally convex or dome-shaped shape, which extends about axis A.

[0098] The spherical portion 32 has two peripheral support surfaces, namely a lower peripheral support surface 32a and an upper peripheral support surface 32b, which extend about axis A. In the example shown, due to the shape of the spherical portion, the lower support surface 32a faces downward (i.e., on the opposite side of the blade 12) and radially outward relative to axis A, while the upper support surface 32b faces upward (i.e., towards the blade 12) and radially outward relative to axis A.

[0099] Figures 3 to 16 The invention illustrates a method for, as Figure 1 and Figure 2 The first embodiment of the system 34 for setting the angular pitch of the blade 10 shown.

[0100] System 34 basically includes hub 36, ring 38, support 40 and nut 42.

[0101] Hub 36 Figure 4 and Figure 5 Shown separately in section 38. Figure 6 Shown separately. The supports 40 are preferably identical, and one of these supports 40 is in Figure 7 As shown in the diagram. Nut 42 can be specifically made in... Figure 3 as well as Figures 9 to 14 I saw it in the middle.

[0102] Figure 3 , Figure 8 as well as Figures 13 to 15 Other components of system 34 are shown; however, these components are optional. This is especially true of bolt 44 and rolling bearings 46, 48.

[0103] Bearings 46 and 48 are mounted around hub 36 between hub 36 and turbine engine housing 50, which may be the hub of a propeller. There are two bearings 46 and 48, namely lower bearing 46 and upper bearing 48.

[0104] Bearings 46 and 48 are rolling bearings with balls. In the example shown, the bearings have different diameters, and the balls in the bearings also have different diameters.

[0105] In the example shown, bearing 46 extends approximately around the lower support surface 32a and / or the free end 28 of the root 14. Bearing 46 has a smaller diameter than the other bearing 48, and the balls of bearing 46 have a larger diameter than the balls of the other bearing 48.

[0106] Bearing 46 has an angled contact. In the example shown, the support point or surface of the ball on the raceway of the ball ring is located on a truncated conical surface 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.

[0107] The bearing 48 extends approximately around the upper support surface 32b of the root 14. The bearing 48 has an angled contact. In the example shown, the support point or surface of the ball on the raceway of the ball ring is located on a truncated conical surface that extends along axis A, and the maximum diameter of the truncated conical surface is located on one side of the free end of the root of the impeller.

[0108] The housing 50 carries the outer rings of bearings 46 and 48, while the inner rings of the bearings are carried by or integrated into the hub 36, as in the example shown for the inner ring of bearing 46.

[0109] Bearings 46 and 48 ensure that hub 36 is centered and guided relative to housing 50 about axis A. Therefore, hub 36 acts as a pivot of blade 10 relative to housing 50.

[0110] Hub 36 includes an annular wall 36a extending about axis A. Wall 36a includes a lower axial end closed by a bottom wall 36b and an open upper axial end, the upper axial end being configured such that the root 14 of blade 10 can be mounted inside hub 36. It is assumed here that axis A of hub 36 is the axis of blade 10, and that the axis of rotation corresponding to the change in blade pitch setting is approximately radial relative to the propeller rotation.

[0111] The bottom wall 36b is configured to fit the free end of the root 14 in a shape-fitting manner, and thus fit the end 28 of the body 24, so that the hub 36 is rotatably fixed to the root 12 about the axis.

[0112] In this context, it should be understood that the bottom wall 36b includes a recess 52 having a non-circular (particularly rectangular) cross-section and is configured to receive the end 28. Figure 3 ). For example in Figure 4As can be seen, the recess 52 is eccentric relative to axis A in a manner similar to that of the end portion 28. This eccentricity enables indexing and error prevention when the root portion 12 is inserted and mounted into the hub portion 36, wherein the end portion 28 has only one possible engagement position in the recess 52.

[0113] The recess 52 is located on the upper or inner surface of the bottom wall 36b of the hub 36, so the recess is located inside the hub 36 and faces the root 12.

[0114] System 34 generates torque at the blade root, which counteracts the torsional torque generated by aerodynamics and centrifugal force. The force transmission between hub 36 and root 12 is direct, wherein the torsional torque is applied directly to the body of the root.

[0115] The bottom wall 36b includes a lower or outer surface located on the side opposite to the root 14 and includes a cylindrical extension 54 extending along axis A and including an external thread or external straight spline 56 for rotatably connecting the system to a pitch changing mechanism (not shown), which is common to the different propeller systems 34 and blades 10 (see [link]). Figure 3 ).

[0116] The outer periphery of the wall 36a of the hub 36 includes a raceway on which the balls of the bearing 46 roll directly. The raceway includes an annular surface with a concave curved cross section. The raceway is located at the lower end of the hub 36 and the wall 36a.

[0117] The inner ring of bearing 48 engages with and surrounds the free upper end 36c of hub 36 and wall 36a. This end of wall 36a includes an outer cylindrical surface for mounting the inner ring and external threads for tightening onto a nut 58, which is designed to be axially supported on the inner ring of bearing 48 to axially secure the inner ring against the outer cylindrical shoulder of hub 36.

[0118] The free upper end portion 36c of the hub 36 includes a surface 36c1 that extends in a plane perpendicular to axis A. Figures 3 to 5 ).

[0119] In the example shown, the wall 36a of the hub 36 includes two annular ribs 60 and 62 at its inner periphery. These two annular ribs extend about axis A and are therefore coaxial. The ribs 60 and 62 are arranged axially apart from each other, and one is above the other, thus being the upper rib 60 and the lower rib 62, respectively.

[0120] The upper rib 60 ensures radial retention of the support 40, and thus ensures radial retention of the root 14 of the blade 10. The rib 62 forms redundancy for these retention devices and ensures fail-safe functionality of the assembly.

[0121] Ribs 60 and 62 define a first annular receiving portion 64 between them, which extends about axis A. Furthermore, the upper rib 60 can be considered to define another receiving portion 66 located above the rib 60, referred to as the upper receiving portion, and the lower rib 62 can be considered to define another receiving portion 68 located below the rib 62, referred to as the lower receiving portion. Figure 3 and Figure 5 ).

[0122] Ribs 60 and 62 extend continuously within a range of less than 360° because they are interrupted by at least one axial notch 70, as in Figure 4 and Figure 5 As can be seen, for example, the notch 70 has an angle range of 20° to 60°, preferably 30° to 50°, around axis A. Therefore, preferably, the ribs 60 and 62 each have an angle range of 300° to 340°, preferably 310° to 330°, around axis A.

[0123] The notch 70 includes sidewalls 70a, which face each other and are connected by a bottom wall 70b facing axis A.

[0124] As in Figure 3a As can be seen, the upper rib 60 includes an inner cylindrical surface 60a at its inner periphery and an annular surface 60b at its lower end, the annular surface extending in a plane perpendicular to axis A.

[0125] The lower rib 62 includes an inner cylindrical surface 62a at its inner periphery, an annular surface 62b extending in a plane perpendicular to axis A at its lower end, and a truncated conical surface 62c at its upper end, the truncated conical surface gradually expanding toward the side of the blade 12 of the impeller 10.

[0126] Between ribs 60 and 62, receiving portion 64 includes an inner cylindrical surface 64a located at the bottom. Receiving portion 68 includes an inner cylindrical surface 68a located at the bottom.

[0127] The ring 38 includes a generally cylindrical intermediate wall 72, which is connected to the lower annular wall 74 at its lower end.

[0128] The intermediate wall 72 is perforated and includes through holes 76. In the example shown, the wall 72 includes an annular row of identical openings 76, which are regularly spaced and distributed around axis A.

[0129] The opening 76 is configured to allow the support 40 to be installed, and is thus sized accordingly. Furthermore, the number of openings 76 is at least equal to the number of supports 40, such that each of the supports 40 can be installed in one of the openings 76.

[0130] The opening 76 has a generally rectangular shape and extends approximately along axis A. The opening 76 is separated from each other by columns 72a in the wall 72. The columns 72a are straight and parallel to each other, and are parallel to axis A.

[0131] The lower wall 74 includes a central hole 74a through which the lower end 28 of the root of the impeller passes, as shown in... Figure 3 As you can see.

[0132] The wall 74 is configured to support the lower support surface 32a of the spherical portion 32 of the root 14 of the blade 10. For example, in Figure 3 As can be seen, the shape of the wall 74 preferably matches the shape of the spherical portion 32 and the support surface 32a. The wall 32 is generally truncated conical in shape and gradually expands outward toward the blade 12 of the impeller 10.

[0133] When the root 14 of the impeller 10 is mounted in the ring 38, the lower support surface 32a of the spherical portion 32 is axially supported on the wall 74. Due to the truncated conical shape of the wall 74 in the example shown, it should be understood that this support has both axial and radial components relative to the axis A at any point.

[0134] At the junction of the lower end of wall 72 and the outer periphery of wall 74, ring 38 includes an annular support surface 75. Figure 3 and Figure 6 ).

[0135] At the upper end of the wall, wall 72 includes a thread 78 for tightening onto nut 42. The thread 78 is located at the outer periphery of ring 38, more specifically, at the outer periphery of the free upper end of ring 38.

[0136] Figure 6 The free upper end of the ring 38 is shown to include an annular toothed portion 80, which is configured to engage with a tool (not shown) for driving the ring 38 to rotate about axis A.

[0137] Figure 6It is also shown that ring 38 may include elements 82 for attaching bolts 44 at the upper end of wall 72 and at the inner periphery of the wall. These attachment elements 82 may take the form of two lugs arranged on either side of one of the openings 76 at the upper end of the opening. These lugs are parallel to each other and parallel to axis A, and each lug includes elements for mounting screws or bolts 84 (see [link to documentation]). Figures 13 to 14 The holes in the lugs are essentially aligned and extend in a plane perpendicular to axis A.

[0138] As in Figure 3 As can be seen, the ring 38 is installed in the hub 36, such that the ring walls 72 and 74 are located in the hub 36, and the free upper end of the ring is located just above the hub 36 and the upper end 36c of the surface 36c1 of the hub.

[0139] The nut 42 includes internal threads, and preferably can be tightened (or at least pre-tightened) onto the threads 78 of the ring 38 before the ring is inserted into the hub 36. The nut 42 can rest axially against the surface 36c1 of the hub 36.

[0140] The pre-tightening of the nut 42 on the ring 38 allows the nut 42 to be axially supported on the surface 36c1, preventing the lower wall 74 of the ring 38 from contacting the hub 36 and the bottom wall 36b of the hub when the ring 38 is inserted. However, preferably, the aforementioned supporting surface 75 of the ring 38 is configured to contact the hub 36 to avoid this axial support of the nut 42 on the surface 36c1.

[0141] When the ring 38 is inserted into the hub 36, the intermediate wall 72 (especially the radial outer surface of the aforementioned post 72a) can slide to engage with the inner cylindrical surfaces 60a and 62a of the ribs 60 and 62 to center and guide the ring 38 in the hub 36.

[0142] Figure 3 and Figures 9 to 14 The nut 42 is shown to include an annular tooth 81 at its upper end, which is configured to engage with a tool (not shown) for driving the nut 42 to rotate about axis A. It can be seen that teeth 80 and 81 are similar.

[0143] The number of supports 40 is at most equal to the number of openings 76 in ring 38. In the example shown, the number of supports 40 is equal to the number of openings 76 minus one, because one of the supports 40 is replaced by a bolt 44. The number of supports 40 is between 5 and 20, preferably between 7 and 11. In the example shown, the number of supports is 9. This means there are nine openings 76 in ring 38.

[0144] Supports 40 are arranged around axis A and mounted in hub 36 around root 14. These supports 40 engage in opening 76 and in at least one of receiving portions 64, 66, 68, and are designed to be supported at least axially on the upper support surface 32b of the spherical portion 32 of root 14.

[0145] Each of the supports 40 includes a support surface 40a located on the upper support surface 32b of the spherical portion 32 at the root. The support surface 40a is shaped such that the support has both an axial component and a radial component relative to axis A at any point.

[0146] Furthermore, each of the supports 40 includes at least one finger that projects radially outward relative to axis A, and in the example shown, two such fingers 86, 88 are included. The fingers 86, 88 are preferably spaced apart and arranged one on top of the other. It should be understood that, in Figure 3 In the example shown, one of the finger portions 86 is intended to engage in the receiving portion 64, and the other finger portion 88 is intended to engage in the receiving portion 68.

[0147] Each support 40 includes an upper finger 86, which includes an upper surface 86a, a lateral surface 86b, and a lower surface 86c. Surfaces 86a and 86b are complementary to surfaces 60b and 64a, and are configured to support the support 40 in the axial and radial directions, respectively, when the support is mounted on these surfaces. Figure 3a As can be seen, surface 86c and surface 62c can be complementary, but a gap can be created between them during assembly or after the nut 42 is tightened.

[0148] Each support 40 includes a lower finger 88, which includes an upper surface 88a, a lateral surface 88b, and a lower surface 88c. Surface 88b is complementary to surface 68a, and surface 88b is configured to support the support 40 in the radial direction on surface 68a, as shown in... Figure 3a As can be seen, surfaces 88a and 62b can be complementary, but a gap can be created between them during assembly or after the nut is tightened.

[0149] Therefore, due to the presence of this gap, the lower finger 88 of each support 40 is not intended to be axially supported on the lower rib 62. If the support 40 breaks, the lower finger 88 of the support can be axially supported on the lower rib 62, which ensures the radial retention of the impeller 10 and forms the aforementioned fail-safe function.

[0150] Advantageously, in the event of a breakage of the upper finger 86 of one or more supports 40, the gap at the lower finger 88 of each support 40 is sufficient to detect the imbalance caused by the displacement of the blade 10.

[0151] The supports 40 are designed to be installed one after another in the openings 76 and the receiving portions 64 and 68 through the recesses 70 formed in the ribs 60 and 62. Thus, the dimensions of the supports 40 allow them to preferably engage in an adjustable manner in the openings 76 and in the recesses 70.

[0152] Therefore, such as Figure 9 As shown, one of the openings 76 must be axially aligned with the recess 70. Then, the first support 40 is inserted into the opening 76 and the recess 70 by a top-to-bottom axial translation, such that the upper finger 86 is located in a plane perpendicular to axis A and passing through the receiving portion 64, while the lower finger 88 is located in a plane perpendicular to axis A and passing through the receiving portion 68. Figure 10 Due to the circumferential abutment between the side of the support 40 and the post 72a of the ring 38, the support 40 is fixed to prevent rotation relative to the ring 38. Therefore, it should be understood that by rotating the ring 38 in the hub 36 using the aforementioned tool, the support 40 can move about axis A away from the notch 70. Figure 11 Other supports are installed in the opening 76 in ring 38 and in receiving portions 64, 68 in the same manner. Figure 12 ).

[0153] Bolt 44 is designed to be installed in the final free opening 76 in ring 38 after support 40 has been installed. Figures 12 to 15 The bolt is also designed to be installed in a recess 70 in the ring 38. The bolt is constructed and specifically sized to be installed in the recess 70 such that the side of the bolt can mate with the sidewall 70a of the recess 70 by circumferential abutment. Figure 15 The bolt 44 is also shown to be radially pressed against the bottom wall surface 70b of the recess 70.

[0154] Bolt 44 is configured to attach to ring 38 and, in the example shown, includes a lateral lug 44a located on lug 82 of ring 38. Lug 44a includes a hole aligned with a hole in lug 82 and intended to receive bolt 84. Bolt 44 is attached to ring 38 such that bolt and ring cannot move relative to each other. Furthermore, engagement of bolt 44 in recess 70 prevents ring 38 from rotating within hub 36.

[0155] Once bolt 44 has been installed, ring 38 can no longer move within hub 36. The position of bolt 44 around the root 14 of blade 10 can be selected. It is advantageous to position the bolt on one side of the suction side 12b of blade 12 of blade 10, closer to the trailing edge 12d of the blade than the leading edge 12c of the blade.

[0156] Once bolt 44 has been installed, nut 42 can be further tightened, and in particular, nut 42 can be tightened onto surface 36c1 in such a way that:

[0157] - The lower wall 74 of the ring 38 is supported on the lower support surface 32a of the spherical portion 32 of the root 14.

[0158] - The upper support surface 32b of the spherical portion 32 is supported on the surface 40a of the support 40, and

[0159] These supports 40 are supported on the surfaces 60b, 64a and 68a of the receiving portions 64 and 68 of the hub 36.

[0160] Figure 16 It is shown that discharge grooves 90 can be formed on the surface 64a of the hub 36, opposite each of the pillars 72. These grooves 90 create discontinuities in the inner cylindrical surface 64a of the hub 36.

[0161] Figure 3a A discharge slot 92 can be provided at the junction between surfaces 60b and 64a, between surfaces 64a and 62c, and / or between surfaces 62b and 68a, such that the junction radius allows for a more uniform distribution of forces and mechanical stresses during operation. In this way, the contact surfaces 60b, 64a, and 68a of the hub 36 are always slightly smaller than the surfaces 86a, 86b, and 88b of the opposing supports 40. This means that there are no localized peak forces (radial and axial support) at the ends of the support surfaces on the hub 36.

[0162] Figure 17 and Figure 17a A variant embodiment of system 34 is shown, particularly a variant embodiment of support 40', which here includes additional fingers 94 that extend axially on one side of blade 12 of impeller 10 at the assembly position, and the additional fingers include radially outward support lateral surfaces 94a.

[0163] As in Figure 17a As can be seen, when the support 40' is installed, surface 86a is intended to be applied axially to surface 60b of rib 60, and surface 94a is intended to be applied axially to surface 60a of the same rib 60. The other surfaces of the support 40' are separated from the surfaces facing the hub 36 by gaps.

[0164] This modification allows for the restriction of stress in the hub 36 and ensures the hub's robustness. The difference between this modification and the initial solution is that the support 40' is centered in the hub 38 not on the maximum outer diameter of the support, but on the inner diameter of the upper finger 86 of the hub 36.

[0165] The radial support (expansion work) of the support 40' is on the inner diameter of the upper rib 60. In this way, the area of ​​the hub 36 that operates under tension (centrifugally holding the impeller 10) is not exposed to this force. Furthermore, since the radial support is on the thicker portion of the hub 36, the deformation of the hub 36 is reduced, which is beneficial to the operation of the upper bearing 48.

[0166] The axial support 40' is axially supported on the lower surface 60b of the upper rib 60 of the hub 36, and the critical region of the support is separated from the critical tensile region of the hub 36 by a sufficient distance.

[0167] The present invention also relates to a method for installing the system 34 as described above, the method comprising the following steps:

[0168] a) Insert ring 38 into hub 36.

[0169] b) Insert the root 14 of the impeller 10 into the ring 38 until the lower support surface 32a of the spherical portion 32 of the root 14 is supported on the lower wall 74 of the ring 38.

[0170] c) The supports 40 and 40' are engaged in the opening 76 in the intermediate wall 72 of the ring 38, and the fingers 86 and 88 of the supports are engaged in the receiving portions 64 and 68 in the hub 36, and

[0171] d) Tighten the nut 42 onto the ring 38 and secure the nut 42 onto the hub 36 (particularly onto surface 36c1) so that the lower wall 74 of the ring 36 is supported on the lower support surface 32a of the spherical portion 32 of the root 14, the upper support surface 32b of the spherical portion 32 is supported on the supports 40, 40', and these supports 40, 40' are supported on the surfaces 60b, 64a, 68a or 60a, 60b of the ribs of the hub 36.

[0172] As described above, step c) preferably includes the following sequential sub-steps:

[0173] c1) By axially translating one of the supports 40 and 40' through the notch 70 in the hub 36, one of the supports 40 and 40' is engaged in one of the openings 76 in the intermediate wall 72 of the ring 38.

[0174] c2) This causes the ring 38 and supports 40, 40' to rotate around axis A inside the hub 36.

[0175] c3) By axially translating another of the supports 40 and 40' through the notch 70 in the hub 36, the other support of the support 40 and 40' is engaged in one of the openings 76 in the intermediate wall 72 of the ring 38.

[0176] c4) Move the ring 38 and the supports 40, 40' to rotate about axis A inside the hub 36; c5) Repeat steps c3) and c4) for the remaining supports 40, 40'.

[0177] c6) By axially translating the bolt 44 through the notch 70 in the hub 36, the bolt 44 is engaged in the final free opening 76 in the intermediate wall 72 of the ring 38, and

[0178] c7) Attach bolt 44 to ring 38.

[0179] Therefore, it should be understood that supports 40, 40' are mounted one after another in the hub 36 via a forced clutch assembly. It should also be understood that supports 40, 40' are mounted one after another in the hub 36 in the same manner as loading a projectile into the rotating barrel of a firearm (hub 36 here corresponds to the barrel).

[0180] In each of steps c2) and c4), ring 38 preferably moves by a circumferential pitch equal to 360° / k, where k is the number of openings 76 in the intermediate wall 72 of ring 38. In the specific case where k equals 9, it should therefore be understood that the circumferential pitch represents 40° around axis A.

[0181] Other variant embodiments, not shown, are possible and include:

[0182] Bolt 44 can be replaced by a device for locking and preventing rotation between ring 38 and hub 36, such as a device located between the upper free end of ring 38 and the upper free end of hub 36;

[0183] Bolt 44 may also be configured to be supported on blade root 14 to participate in the retention of blade root and to participate in absorbing forces acting on blade during operation, which is not the case in the previous embodiments; therefore, bolt 44 may be formed by one of the supports 40, 40', which will be associated with means for attachment to ring 38 and / or hub 36.

[0184] This invention has many advantages, including:

[0185] - The system’s quick and easy assembly allows the blade 10 to be replaced without disassembling the engine or hub 36.

[0186] - A highly secure and reliable solution:

[0187] - If the upper rib of the hub 36 breaks, the impeller 10 is held by the lower rib 62 (fail-safe), and the upper end 36c of the hub 36 is also held by the nut 42.

[0188] - In the event that all the posts 72a of the ring 38 break, the blade 10 is still held by the upper rib 60 (without pre-tightening), and the upper end of the ring 38 is still fixed around the blade root 14.

[0189] -If one of the supports 40 and 40' breaks, there are still enough supports to maintain the impeller 10 (redundancy);

[0190] - Design details (such as the positioning slots 90, 92 and the discharge groove) contribute to the robustness of the component; - The impeller 10 is well held in place during all stages of operation.

Claims

1. A system (34) for controlling the pitch setting of the propeller blades (10) of an aircraft turbine engine, characterized in that, The system includes: - A blade (10), the blade comprising a blade (12) connected to a root (14), the blade comprising a pitch axis (A), the root (14) comprising a spherical portion (32) having two supporting surfaces, the two supporting surfaces being a lower supporting surface (32a) and an upper supporting surface (32b), the two supporting surfaces extending about the axis (A). - Hub (36), the hub including an annular wall (36a) extending about the axis (A), the annular wall (36a) including a lower axial end closed by a bottom wall (36b) and an open upper axial end, the upper axial end being configured such that the root (14) of the blade (10) can be mounted inside the hub (36), the bottom wall (36b) including a recess (52) having a non-circular cross section and being configured to receive a free end (28) complementary in shape to the root (14), such that the hub (36) is rotatably fixed to the root (14) about the axis (A). - A ring (38) extending about the axis (A) and mounted around the root (14) and in the hub (36), the ring (38) including a lower wall (74) located in the hub (36) and including an orifice (74a) through which the free end (28) of the root (14) passes, the lower support surface (32a) of the spherical portion (32) of the root (14) being configured to be supported at least axially on the lower wall (74) on a side opposite to the blade (12) of the impeller (10), the ring (38) also including a perforated intermediate wall (72) and a thread (78) at the upper end. - Supports (40, 40'), arranged around the axis (A), and mounted around the root (14) and in the hub (36), these supports (40, 40') engaging in openings (76) in the intermediate wall (72) and engaging in at least one receiving portion (64, 68) of the annular wall (36a) of the hub (36), the upper support surface (32b) of the spherical portion (32) of the root (14) being configured to be supported on these supports (40, 40') at least in the axial direction, supported on the same side as the blade (12) of the impeller (10), and - A nut (42), which is screwed onto the thread (78) of the ring (38) and configured to be axially supported on the hub (36), such that the tightening of the nut (42) causes the lower wall (74) of the ring (38) to be supported on the lower support surface (32a) of the spherical portion (32) of the root (14), the upper support surface (32b) of the spherical portion (32) to be supported on the supports (40, 40'), and the supports (40, 40') to be supported on the complementary support surfaces (60a, 60b, 64a, 68a) of the at least one receiving portion (64, 68) of the hub (36).

2. The system (34) according to claim 1, wherein, The number of the supports (40, 40') is less than or equal to the number of the openings (76) in the intermediate wall (72) of the ring (38), each of the supports (40, 40') engaging in one of these openings (76).

3. The system (34) according to claim 2, wherein, The number of the supports (40, 40') ranges from 5 to 20.

4. The system (34) according to any one of claims 1 to 3, wherein, The lower wall (74) of the ring (38) has a truncated conical shape that expands toward the blade (12), such that the lower support surface (32a) of the spherical portion (32) of the root (14) has an axial and radial component relative to the axis (A) at each point on the lower wall (74).

5. The system (34) according to any one of claims 1 to 3, wherein, Each of the supports (40, 40') includes a support surface (40a) on the upper support surface (32b) of the spherical portion (32) of the root (14), the support surface (40a) being shaped such that the support has an axial component and a radial component relative to the axis (A) at any point.

6. The system (34) according to any one of claims 1 to 3, wherein, The nut (42) is screwed onto the outside of the ring (38) and / or axially supported on the upper free end (36c) of the hub (36).

7. The system (34) according to any one of claims 1 to 3, wherein, Each of the supports (40, 40') includes at least one finger (86, 88) that protrudes radially outward relative to the axis (A), and the at least one finger (86, 88) includes an upper surface (86a) that is axially supported on a corresponding support surface (60b) of the at least one receiving portion (64).

8. The system (34) according to claim 7, wherein, The at least one finger (86, 88) further includes a lateral surface (86b) that is radially outwardly supported on a corresponding support surface (64a) of the at least one receiving portion (64).

9. The system (34) according to claim 7, wherein, Each of the supports (40, 40') includes two fingers (86, 88) that project radially outward relative to the axis (A) and are arranged axially behind the other.

10. The system (34) according to any one of claims 1 to 3, wherein, The hub (36) includes at least one annular rib extending about the axis (A) and defining at least one receiving portion (64, 68) for engaging the support (40, 40'), the annular rib including at least one axial recess (70) configured such that the supports (40, 40') can be installed one after another.

11. The system (34) according to claim 10, wherein, The hub (36) includes two annular ribs, an upper rib (60) and a lower rib (62), which extend about the axis (A) and define between the two annular ribs at least one receiving portion (64) for engaging the support (40, 40'). The annular ribs include at least one axial recess (70) configured to allow the supports (40, 40') to be installed one after the other.

12. The system (34) according to claim 10, wherein, The system also includes at least one bolt (44) which engages in one of the openings (76) of the ring (38) and in the at least one recess (70) attached to the ring (38).

13. The system (34) according to claim 12, wherein, The bolt (44) is attached to the ring (38) by one or more screws (84).

14. The system (34) according to claim 12 or 13, wherein, The bolt (44) is located on the suction side (12b) of the blade (12) of the impeller (10), and closer to the trailing edge (12d) of the blade (12) than to the leading edge (12a) of the blade.

15. The system (34) according to claim 12 or 13, wherein, Before the bolt (44) is installed, the ring (38) is rotatably movable about the axis (A) in the hub (36). After the bolt (44) is installed, the ring (38) is prevented from rotating about the axis (A) by the circumferential abutment of the bolt (44) on the side of the recess (70).

16. A turbine engine comprising at least one system (34) according to any one of claims 1 to 15.

17. The turbine engine according to claim 16, wherein, The turbine engine is a turbine engine used in aircraft.

18. A method for installing the system (34) according to any one of claims 1 to 15, wherein, The method includes the following steps: a) Insert the ring (38) into the hub (36), b) Insert the root (14) of the blade (10) into the ring (38) until the lower support surface (32a) of the spherical portion (32) of the root (14) is supported on the lower wall (74) of the ring (38). c) engaging the support (40, 40') into the opening (76) in the intermediate wall (72) of the ring (38), and engaging it into at least one receiving portion (64, 68) of the hub (36), and d) Tighten the nut (42) onto the ring (38) and secure the nut (42) onto the hub (36) such that the lower wall (74) of the ring (38) rests on the lower support surface (32a) of the spherical portion (32) of the root (14), the upper support surface (32b) of the spherical portion (32) rests on the supports (40, 40'), and these supports (40, 40') rest on the complementary support surfaces (60a, 60b, 64a, 68a) of at least one receiving portion (64, 68) of the hub (36).

19. The method of claim 18, wherein the system is as defined in claim 15, wherein, Step c) includes the following consecutive sub-steps: c1) By axially translating one of the supports (40, 40') through the notch (70) in the hub (36), one of the supports (40, 40') is engaged in one of the openings (76) in the intermediate wall (72) of the ring (38). c2) to cause the ring (38) and the support (40, 40') to rotate about the axis (A) inside the hub (36), c3) By axially translating another of the supports (40, 40') through the notch (70) in the hub (36), the other support of the supports (40, 40') is engaged in one of the openings (76) in the intermediate wall (72) of the ring (38). c4) causes the ring (38) and the supports (40, 40') to rotate about the axis (A) inside the hub (36). c5) For the remaining supports (40, 40'), repeat steps c3) and c4). c6) By axially translating the bolt (44) through the notch (70) in the hub (36), the bolt (44) is engaged in the final free opening (76) in the intermediate wall (72) of the ring, and c7) Attach the bolt (44) to the ring (38).

20. The method according to claim 19, wherein, In each of steps c2) and c4), the ring (38) moves by a circumferential pitch equal to 360° / k, where k is the number of openings (76) in the intermediate wall (72) of the ring (38).

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