Turbine engine with variable pitch airfoil assembly

Abstract

A turbine engine includes a fan section, a compressor section, a combustion section, and a turbine section in a serial flow arrangement and defining a stator portion and a rotor portion, the rotor portion rotating about an engine centerline. The rotor portion includes a variable pitch airfoil assembly. A variable pitch airfoil assembly has an airfoil and a balancing insert.

Description

Technical Field

[0001] The present disclosure relates generally to turbine engines having airfoil assemblies, and more particularly to turbine engines having variable pitch airfoil assemblies. Background Art

[0002] A turbine engine, particularly a gas or combustion turbine engine, is a rotary engine that extracts energy from a flow of gas that passes through a fan having a plurality of fan blades, then enters the engine through a series of compressor stages (which include pairs of rotating blades and stationary vanes), through a combustor, and then through a series of turbine stages (which include pairs of rotating blades and stationary vanes). The blades are mounted to a rotating disk, and the vanes are mounted to a stator disk.

[0003] During operation, air is brought into the compressor section through the fan section, where it is then pressurized and mixed with fuel and ignited in the combustor to produce hot combustion gases, which flow downstream through the turbine stage where the air expands and exits the exhaust section. The expansion of the air in the turbine section is used to drive the rotating sections of the fan section and the compressor section. The intake of air, the pressurization of air, and the expansion of air are accomplished in part by the rotation of various rotating blades mounted to respective disks that extend through the fan section, the compressor section, and the turbine section, respectively. The rotation of the rotating blades applies mechanical stresses along various portions of the blades; specifically, where the blades are mounted to the disks.

[0004] In some turbine engines, a variable pitch airfoil may be included that can be selectively rotated about a generally spanwise axis to adjust or otherwise customize the flow of fluid over the variable pitch airfoil. The variable pitch airfoil can be moved using a trunnion and a spar. The trunnion can be rotated about an axis of rotation, which in turn rotates the spar and the variable pitch airfoil. The trunnion is coupled to the spar or otherwise formed with the spar. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] A full and enabling disclosure of the present disclosure, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0006] Figure 1 is a schematic cross-sectional view of a turbine engine, which is an unducted or open rotor turbine engine according to an exemplary embodiment of the present disclosure.

[0007] Figure 2 Is suitable for Figure 1 Schematic diagram of an airfoil assembly used in a turbine engine, the airfoil assembly comprising an airfoil, a trunnion and a spar.

[0008] Figure 3 Is it like Figure 2 A schematic cross-sectional view of a portion of an airfoil assembly as viewed along section line III-III, further illustrating a sleeve disposed on a portion of a spar, and a balancing insert disposed along a portion of the sleeve.

[0009] Figure 4 Suitable for use as Figure 2 A schematic cross-sectional view of an exemplary airfoil assembly of an airfoil assembly of further illustrating a trunnion, a spar including an inner portion, and a balancing insert including a first body and a second body, the balancing insert being disposed within a portion of the inner portion.

[0010] Figure 5 Suitable for use as Figure 2 A schematic cross-sectional view of an exemplary airfoil assembly of an airfoil assembly further illustrating a trunnion, a spar including an interior, and a balancing insert including a first body, a second body and a rib, the balancing insert being disposed within a portion of the interior. DETAILED DESCRIPTION

[0011] Various aspects disclosed herein relate to an airfoil assembly for a turbine engine. The airfoil assembly includes an airfoil, a spar, and a trunnion. The spar couples the airfoil to the trunnion. The trunnion can mount the airfoil assembly to a rotatable component (e.g., a disk). The airfoil assembly also includes a sleeve extending over a corresponding portion of the spar and at least one balancing insert disposed along the sleeve or disposed within an interior of the spar.

[0012] Balance inserts can be used to balance airfoil assemblies, particularly airfoil assemblies with variable pitch. The balance of airfoil assemblies is used to reduce imbalances within the airfoil assemblies, thereby reducing vibration stresses. In addition, balance inserts can be used to balance multiple airfoil assemblies mounted to a common rotatable component. At least one of the multiple airfoil assemblies may include a corresponding balance insert to ensure that the multiple airfoil assemblies remain balanced at all times. For the purpose of illustration, the present disclosure will be described with respect to airfoil assemblies for turbine engines, particularly fan blades of turbine engines. However, it should be understood that the various aspects of the present disclosure described herein are not limited thereto and may have general applicability in other engines or in other parts of turbine engines. For example, the present disclosure may be applicable to airfoil assemblies in other engines or vehicles, and may be used to provide benefits in industrial, commercial and residential applications.

[0013] As used herein, the term "upstream" refers to the direction opposite to the direction of fluid flow, and the term "downstream" refers to the direction in the same direction as the direction of fluid flow. The terms "front" or "frontward" refer to in front of something, and "rear" or "rearward" refer to behind something. For example, when used with respect to fluid flow, front / front may refer to upstream, while rear / rearward may refer to downstream.

[0014] Additionally, as used herein, the term "radial" or "radially" refers to a direction away from a common center. For example, in the overall context of a turbine engine, radial refers to a direction along a ray extending between a central longitudinal axis of the engine and an outer circumference of the engine. Additionally, as used herein, the term "group" or a "group" of elements may be any number of elements, including only one.

[0015] Furthermore, as used herein, the term "fluid" or its repeated forms may refer to any suitable fluid within the gas turbine engine to which at least a portion of the gas turbine engine is exposed, such as, but not limited to, combustion gases, ambient air, a pressurized gas stream, a working gas stream, or any combination thereof. It is further contemplated that the gas turbine engine may be other suitable turbine engines, such as, but not limited to, a steam turbine engine or a supercritical carbon dioxide turbine engine. As non-limiting examples, the term "fluid" may refer to steam in a steam turbine engine, or to carbon dioxide in a supercritical carbon dioxide turbine engine.

[0016] All directional references (e.g., radial, axial, proximal, distal, upper, lower, upward, downward, left, right, lateral, front, rear, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, forward, backward, etc.) are used only for identification purposes to help the reader understand the present disclosure, and do not create limitations, especially limitations on the position, orientation, or use of the various aspects of the present disclosure described herein. Connection references (e.g., attachment, coupling, fixing, fastening, connection, and engagement) should be interpreted broadly and may include intermediate members between sets of elements and relative motion between elements, unless otherwise specified. Therefore, connection references do not necessarily infer that two elements are directly connected and have a fixed relationship to each other. The exemplary drawings are for illustrative purposes only, and the dimensions, positions, orders, and relative sizes reflected in the attached drawings may vary.

[0017] The term "composite" as used herein refers to a component having two or more materials. A composite component can be a combination of at least two or more metals, non-metals, or a combination of metal and non-metal elements or materials. Examples of composite materials can be, but are not limited to, polymer matrix composites (PMC), ceramic matrix composites (CMC), metal matrix composites (MMC), carbon fibers, polymer resins, thermoplastic resins, bismaleimide (BMI) materials, polyimide materials, epoxy resins, glass fibers, and silicon matrix materials.

[0018] As used herein, a "composite" component refers to a structure or component that includes any suitable composite material. A composite component, such as a composite airfoil, may include multiple layers or plies of composite material. The stiffness, material, and dimensions of the layers or plies may be varied to achieve a desired composite component or composite portion of a component having a predetermined weight, size, stiffness, and strength.

[0019] One or more layers of adhesive may be used to form or join the composite components. The adhesive may include resins and phenolics, where the adhesive may require curing at elevated temperatures or other hardening techniques.

[0020] As used herein, PMC refers to a class of materials. For example, PMC materials are defined in part by prepregs, which are reinforcing materials pre-impregnated with polymer matrix materials such as thermoplastic resins. Non-limiting examples of processes for producing thermoplastic prepregs include hot melt prepregs, in which fiber reinforcements are pulled through a resin bath; and powder prepregs, in which resins are electrostatically deposited onto fiber reinforcements as a non-limiting example, and then adhered to the fibers in an oven or with the help of heated rollers as a non-limiting example. Prepregs can be in the form of unidirectional tapes or woven fabrics, which are then stacked one on top of another to form the required number of stacked composite plies of a part.

[0021] The multilayer prepreg is stacked to the appropriate thickness and orientation of the composite part, and then the resin is cured and solidified to provide a fiber reinforced composite part. The resin used for PMC matrix materials can generally be divided into thermosetting resins and thermoplastic resins. Thermoplastic resins are generally classified as polymers that can be repeatedly softened and flowed when heated due to physical changes rather than chemical changes, and hardened when fully cooled. Famous examples of thermoplastic resins include nylon, thermoplastic polyesters, polyaryletherketones and polycarbonate resins. Specific examples of high-performance thermoplastic resins considered for aerospace applications include polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyaryletherketone (PAEK) and polyphenylene sulfide (PPS). In contrast, once fully cured into a hard solid, thermosetting resins do not soften significantly when heated, but thermally decompose when fully heated. Famous examples of thermosetting resins include epoxy resins, bismaleimide (BMI) and polyimide resins.

[0022] In another non-limiting example, by using thermoplastic polymers, woven fabrics can be used instead of using prepregs. Woven fabrics may include, but are not limited to, dry carbon fibers woven together with thermoplastic polymer fibers or filaments. Non-prepreg woven structures can be manufactured in a similar manner. In this way, the fiber volume of a part can be customized by specifying the relative concentrations of thermoplastic fibers and reinforcing fibers that have been woven or woven together. In addition, different types of reinforcing fibers can be woven or woven together at different concentrations to customize the performance of the part. For example, glass fibers, carbon fibers, and thermoplastic fibers can all be woven together at different concentrations to customize the performance of the part. Carbon fibers provide the strength of the system, glass fibers can be combined to enhance impact performance, which is a design feature of parts located near the engine inlet, and thermoplastic fibers provide bonding for the reinforcing fibers.

[0023] In yet another non-limiting example, resin transfer molding (RTM) can be used to form at least a portion of the composite component. Generally speaking, RTM includes applying a dry fiber or matrix material to a mold or cavity. The dry fiber or matrix material may include prepregs, braided materials, woven materials, or any combination thereof.

[0024] The resin may be pumped or otherwise provided to the mold or cavity to impregnate the dry fibers or matrix material. The impregnated fiber or matrix material and resin combination is then cured and removed from the mold. After removal from the mold, the composite part may require a post-curing process.

[0025] It is contemplated that RTM may be a vacuum assisted process. That is, the air in the cavity or mold may be removed and replaced with resin prior to heating or curing. It is also contemplated that placement of dry fiber or matrix material may be manual or automated.

[0026] The dry fiber or matrix material may be shaped to shape the composite part or to guide the resin. Optionally, additional layers or reinforcements of a material different from the dry fiber or matrix material may also be included or added prior to heating or curing.

[0027] As used herein, CMC refers to a class of materials having reinforcing fibers in a ceramic matrix. Generally, the reinforcing fibers provide structural integrity to the ceramic matrix. Some examples of reinforcing fibers may include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), non-oxide carbon-based materials (e.g., carbon), oxide ceramics (e.g., silicon oxycarbide, silicon oxynitride, aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates (e.g., mullite), or mixtures thereof), or mixtures thereof.

[0028] Some examples of ceramic matrix materials may include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), oxide ceramics (e.g., silicon oxycarbide, silicon oxynitride, aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates, or mixtures thereof), or mixtures thereof. Optionally, ceramic particles (e.g., oxides of Si, Al, Zr, Y, and combinations thereof) and inorganic fillers (e.g., pyrophyllite, wollastonite, mica, talc, kyanite, and montmorillonite) may also be included in the ceramic matrix.

[0029] In general, specific CMCs can be referred to as their fiber type / matrix type combination. For example, C / SiC is carbon fiber reinforced silicon carbide; SiC / SiC is silicon carbide fiber reinforced silicon carbide, SiC / SiN is silicon carbide fiber reinforced silicon nitride; SiC / SiC-SiN is silicon carbide fiber reinforced silicon carbide / silicon nitride matrix mixture, etc. In other examples, CMCs can be composed of a matrix and reinforcing fibers, and the reinforcing fibers include oxide-based materials such as aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminosilicates, and mixtures thereof. Aluminosilicates can include crystalline materials such as mullite (3Al2O3·2SiO2), as well as glassy aluminosilicates.

[0030] In certain embodiments, the reinforcing fibers may be bundled and / or coated before being included in the matrix. For example, the fiber bundles may be formed into reinforcing tapes, such as unidirectional reinforcing tapes. Multiple tapes may be stacked together to form a preformed component. The fiber bundles may be impregnated with a slurry composition before or after forming the preform. The preform may then undergo a thermal treatment and subsequent chemical treatment to obtain a component formed of a CMC material having a desired chemical composition. For example, the preform may undergo curing or burnout to produce a high carbon residue in the preform, and then melt infiltrated with silicon, or cured or pyrolyzed to produce a silicon carbide matrix in the preform, and then chemically infiltrated with silicon carbide. Before or after chemical vapor infiltration, additional steps may be taken to improve the densification of the preform by injecting a liquid resin or polymer into the preform, followed by a thermal treatment step to fill the voids with silicon carbide. The CMC materials used herein may be formed using any known or hereafter developed method including, but not limited to, melt infiltration, chemical vapor infiltration, polymer infiltration pyrolysis (PIP), or any combination thereof.

[0031] Such materials, along with certain monolithic ceramics (i.e., ceramic materials without reinforcement materials), are particularly well suited for higher temperature applications. In addition, these ceramic materials are lightweight compared to superalloys, but can still provide strength and durability to components made therefrom. As a result, such materials are currently being considered for use in many gas turbine components used in the higher temperature sections of gas turbine engines, such as airfoils (e.g., turbines and buckets), combustors, shrouds, and other similar components that would benefit from the lighter materials and higher temperature capabilities that these materials can provide.

[0032] The term "metal" as used herein refers to materials including metals, such as but not limited to titanium, iron, aluminum, stainless steel, and nickel alloys. A metal material or alloy may be a combination of at least two or more elements or materials, at least one of which is a metal.

[0033] Figure 1 is a schematic cross-sectional view of a turbine engine, particularly an open rotor or unducted turbine engine 10 for an aircraft. Unducted turbine engine 10 has a generally longitudinally extending axis or engine centerline 12 extending from a forward end 14 to an aft end 16. Unducted turbine engine 10 includes, in downstream serial flow relationship, a set of circumferentially spaced blades or propellers defining a fan section 18 including a fan 20; a compressor section 22 including a supercharger or low pressure (LP) compressor 24 and a high pressure (HP) compressor 27; a combustion section 28 including a combustor 30; a turbine section 32 including an HP turbine 34, and an LP turbine 36; and an exhaust section 38. Unducted turbine engine 10 as described herein is meant to be a non-limiting example, and other architectures are possible, such as, but not limited to, a steam turbine engine, a supercritical carbon dioxide turbine engine, or any other suitable turbine engine.

[0034] An exterior surface of ductless turbine engine 10 defined by casing or nacelle 40 extends from a forward end 14 of ductless turbine engine 10 toward an aft end 16 of ductless turbine engine 10 and covers compressor section 22, combustion section 28, turbine section 32, and at least a portion of exhaust section 38. Fan section 18 may be positioned at a forward portion of nacelle 40 and extends radially outward from nacelle 40 of ductless turbine engine 10, specifically, fan section 18 extends radially outward from nacelle 40. Fan section 18 includes a set of fan blades 42 and a set of stationary fan blades 82 downstream of the set of fan blades 42, both radially disposed from and circumferentially disposed about engine centerline 12. Ductless turbine engine 10 includes any number of one or more sets of rotating blades or propellers (e.g., a set of fan blades 42) disposed upstream of a set of stationary fan blades 82. As a non-limiting example, ductless turbine engine 10 may include multiple sets of fan blades 42 or fan blades 82. Therefore, unducted turbine engine 10 is further defined as an unducted single fan turbine engine. Unducted turbine engine 10 is further defined by the position of fan section 18 relative to combustion section 28. Fan section 18 may be located upstream, downstream, or in line with the axial orientation of combustion section 28.

[0035] Compressor section 22 , combustion section 28 , and turbine section 32 are collectively referred to as an engine core 44 , which produces combustion gases. Engine core 44 is surrounded by an engine casing 46 operably coupled to a portion of nacelle 40 of ductless turbine engine 10 .

[0036] An HP shaft or spool 48 is coaxially disposed about the engine centerline 12 of the ductless turbine engine 10, drivingly connecting the HP turbine 34 to the HP compressor 27. An LP shaft or spool 50, coaxially disposed within the larger diameter annular HP spool 48 about the engine centerline 12 of the ductless turbine engine 10, drivingly connects the LP turbine 36 to the LP compressor 24 and the fan 20. The spools 48, 50 are rotatable about the engine centerline 12 and are coupled to a set of rotatable elements that collectively define a rotor 51.

[0037] It should be appreciated that unducted turbine engine 10 is a direct drive or integral drive engine that utilizes a reduction gearbox to couple LP shaft or spool 50 to fan 20 .

[0038] The LP compressor 24 and the HP compressor 27 each include a set of compressor stages 52, 54, wherein a set of compressor blades 56, 58 rotate relative to a corresponding set of static compressor vanes 60, 62 (also referred to as nozzles) to compress or pressurize a fluid flow passing through the stage. In a single compressor stage 52, 54, a plurality of compressor blades 56, 58 are arranged in a ring and extend radially outward relative to the engine centerline 12, from a blade platform to a blade tip, while a corresponding static compressor vane 60, 62 is positioned upstream of and adjacent to the compressor blades 56, 58. It should be noted that Figure 1 The numbers of blades, buckets, and compressor stages shown in FIG. 5 are selected for illustrative purposes only, and other numbers are possible.

[0039] The compressor blades 56, 58 for the stages of the compressor section 22 are mounted to disks 61 mounted to a corresponding one of the HP spool 48 and the LP spool 50, with each stage having its own disk 61. The static compressor buckets 60, 62 for the stages of the compressor section 22 are mounted to the engine case 46 in a circumferential arrangement.

[0040] The HP turbine 34 and the LP turbine 36 each include a set of turbine stages 64, 66 in which a set of turbine blades 68, 70 rotate relative to a corresponding set of static turbine vanes 72, 74 (also referred to as nozzles) to extract energy from the fluid flow passing through the stage. In a single turbine stage 64, 66, a plurality of turbine blades 68, 70 are arranged in a ring and extend radially outward relative to the engine centerline 12, from the blade platform to the blade tip, while the corresponding static turbine vanes 72, 74 are positioned upstream of and adjacent to the turbine blades 68, 70. It should be noted that Figure 1 The number of blades, buckets, and turbine stages shown in FIG. 5 are selected for illustrative purposes only, and other numbers are possible.

[0041] Turbine blades 68, 70 for the stages of turbine section 32 are mounted to disks 71 mounted to respective ones of HP spool 48 and LP spool 50, with each stage having a dedicated disk 71. Static turbine buckets 72, 74 for the stages of turbine section 32 are mounted to engine case 46 in a circumferential arrangement.

[0042] Rotating portions of ductless turbine engine 10, such as blades 56, 58, 68, 70 in compressor section 22 and turbine section 32, are also individually or collectively referred to as rotors 51. Thus, rotor 51 refers to the combination of rotating elements of the entire ductless turbine engine 10.

[0043] In addition to the rotating parts, the stationary parts of the ductless turbine engine 10, such as the static blades 60, 62, 72, 74 in the compressor section 22 and the turbine section 32, are also individually or collectively referred to as stators 63. Therefore, the stator 63 refers to the combination of non-rotating elements of the entire ductless turbine engine 10.

[0044] Nacelle 40 is operably coupled to ductless turbine engine 10 and covers at least a portion of engine core 44, engine case 46, or exhaust section 38. At least a portion of nacelle 40 extends axially forward or upstream of the position shown. For example, nacelle 40 extends axially forward such that a portion of nacelle 40 covers or covers a portion of fan section 18 or a supercharger section (not shown) of ductless turbine engine 10.

[0045] It should be understood that the ductless turbine engine 10 may be divided into at least two separate portions; a rotor portion and a stator portion. The rotor portion may be defined as any portion of the ductless turbine engine 10 that rotates about a respective axis of rotation. The stator portion may be defined by a combination of non-rotating elements disposed within the ductless turbine engine 10. As non-limiting examples, the rotor portion may include a plurality of fan blades 42, compressor blades 56, 58, or turbine blades 68, 70. As non-limiting examples, the stator portion may include a plurality of fan blades 82, static compressor blades 60, 62, or static turbine blades 72, 74.

[0046] During operation of unducted turbine engine 10, freestream airflow 79 flows against a forward portion of unducted turbine engine 10. A portion of freestream airflow 79 enters annular region 25 defined by the outer surface of nacelle 40 and the swept area between the tips of fan blades 42, where the airflow is inlet airflow 78. A portion of inlet airflow 78 enters engine core 44 and is described as working airflow 76, which is used for combustion within engine core 44.

[0047] More specifically, a working air stream 76 flows into the LP compressor 24, which then pressurizes the working air stream 76, thereby defining a pressurized air stream that is supplied to the HP compressor 27, which further pressurizes the air. The working air stream 76, or pressurized air stream, from the HP compressor 27 is mixed with fuel and ignited in the combustor 30, thereby producing combustion gases. The HP turbine 34 extracts some work from these gases, which drives the HP compressor 27. The combustion gases are discharged to the LP turbine 36, which extracts additional work to drive the LP compressor 24, and the working air stream 76, or exhaust gases, are ultimately discharged from the unducted turbine engine 10 via the exhaust section 38. The drive of the LP turbine 36 drives the LP spool 50 to rotate the fan 20 and the LP compressor 24. The working air stream 76, including the pressurized air stream and the combustion gases, defines the working air stream flowing through the compressor section 22, the combustion section 28, and the turbine section 32 of the unducted turbine engine 10.

[0048] Inlet airflow 78 flows over a set of fan blades 42, over at least a portion of a set of stationary fan blades 82, and nacelle 40 of unducted turbine engine 10. Inlet airflow 78 then flows over a set of stationary fan blades 82, following the curvature of nacelle 40 and toward exhaust section 38. Pylon 84 mounts unducted turbine engine 10 to an external structure (e.g., a fuselage, wing, tail, etc. of an aircraft).

[0049] Working airflow 76 and at least some inlet airflow 78 merge downstream of exhaust section 38 of unducted turbine engine 10 . Working airflow 76 and inlet airflow 78 together create the overall thrust of unducted turbine engine 10 .

[0050] It is contemplated that a portion of the working airflow 76 is extracted as bleed air 77 (e.g., from the compressor section 22). The bleed air 77 provides airflow to engine components that require cooling. The temperature of the working airflow 76 leaving the combustor 30 is significantly increased relative to the working airflow 76 within the compressor section 22. Therefore, the cooling provided by the bleed air 77 is necessary for operating such engine components in a high temperature environment or in the hot part of the unducted turbine engine 10. In the context of a turbine engine, the hot part of the engine is typically located downstream of the combustor 30, particularly downstream of the turbine section 32, with the HP turbine 34 being the hottest part because it is located directly downstream of the combustion section 28. Other sources of cooling fluid are, but are not limited to, fluid discharged from the LP compressor 24 or the HP compressor 27.

[0051] Figure 2 Is suitable for Figure 11 is a schematic diagram of an airfoil assembly 130 for use within a turbine engine 10 of the type shown in FIG. The airfoil assembly 130 may include an airfoil 132, which is any suitable airfoil of the turbine engine 10. As non-limiting examples, the airfoil 132 may be a blade of the plurality of fan blades 42, or a blade from the compressor blades 56, 58 or the turbine blades 68, 70. In the event that the airfoil 132 is a blade, the airfoil assembly 130 may be disposed within a rotor portion of the turbine engine 10. It is contemplated that the airfoil 132 may be a blade, bucket, airfoil, or other component of any turbine engine, such as, but not limited to, a gas turbine engine, a turboprop engine, a turboshaft engine, a ducted turbofan engine, an unducted turbofan engine, or an open rotor turbine engine.

[0052] The airfoil 132 may include an outer wall 138 defining an airfoil interior 148. The outer wall 138 may extend between a leading edge 144 and a trailing edge 146 to define a chord-wise direction (C). The outer wall 138 may also extend between a root 140 and a tip 142 to define a span-wise direction (S). The outer wall 138 may be a composite wall made of one or more layers of composite material. The one or more layers of material may be applied during the same stage or different stages of manufacture of the airfoil 132.

[0053] At least a portion of the airfoil 132 may include a composite material, such that the airfoil assembly 130 may be defined as a composite airfoil assembly. As a non-limiting example, the outer wall 138 may include at least a PMC portion or a polymer portion. The PMC may include, but is not limited to, a matrix of thermosetting materials (epoxy resins, phenolic resins) or thermoplastic materials (polycarbonate, polyvinyl chloride, nylon, acrylic resins) and embedded glass, carbon, steel, or Kevlar fibers. It should be understood that the airfoil 132 may include a composite material, a metallic material, any other suitable material, or a combination thereof.

[0054] The airfoil assembly 130 may also include a spar 136 and a trunnion 134. The spar 136 may extend into the airfoil interior 148. The spar 136 may extend from the root 140. The spar 136 may be operably coupled to the trunnion 134. The trunnion 134 may include any suitable material, such as, but not limited to, a metallic material or a composite material. It should be understood that the term composite material may also include metal but having a composite framework (e.g., a metal matrix composite material). In the case of a composite material, the trunnion 134 may be any suitable composite material, such as a 2D or 3D composite material, a laminated skin, a woven or braided composite material, or any other suitable composite material.

[0055] The airfoil 132 has a span length (L) measured along the spanwise direction (S) from a root 140 at 0% of the span length (L) to a tip 142 at 100% of the span length (L). The entirety of the spar 136 may be located less than 20% of the span length (L). Alternatively, the spar 136 may extend over 20% of the span length (L).

[0056] The airfoil assembly 130 may be defined by a center of mass (CM). The center of mass (CM) may be disposed along any portion of the airfoil assembly 130 or offset from the airfoil assembly 130 .

[0057] During operation of the airfoil assembly 130, the trunnion 134 may rotate in a rotational direction (Rd) about a pitch axis (Pax). When the spar 136 couples the trunnion 134 to the airfoil 132, the rotation of the trunnion 134 in the rotational direction (Rd) causes the airfoil 132 to rotate about the pitch axis (Pax). This rotation may be used to control the pitch of the airfoil assembly 130, such that the airfoil assembly 130 is defined as a variable pitch airfoil assembly. Therefore, the airfoil assembly 130 may be defined as a variable pitch airfoil assembly. The pitch of the airfoil assembly 130 may be based on the turbine engine (e.g., Figure 1 The working airflow (Fw) may flow through a corresponding portion of the airfoil assembly 130 , and in particular, through the airfoil 132 .

[0058] Figure 3 Is it like Figure 2 Schematic cross-sectional view of a portion of the airfoil assembly 130 as viewed along section line III-III. For illustrative purposes, the airfoil 132 ( Figure 2 ).

[0059] The trunnion 134 includes a wall 151 having a set of interior surfaces 152 that at least partially define a socket 154. The trunnion 134 includes an upper edge 155 that defines an open top 156 leading to the socket 154. When the spar 136 is received within the airfoil interior 148 ( Figure 2 ), at least a portion of the trunnion 134 may face the airfoil 132 ( Figure 2 ).

[0060] The spar 136 includes a centerline axis 150. The spar 136 extends through an open top 156 and into a portion of the socket 154. As shown, the spar 136 is received within a corresponding portion of the socket 154.

[0061] The spar 136 terminates at a distal end 160 within the socket. The spar 136 may include an interior surface 162 that defines a spar interior 164. The spar interior 164 defines a void within the spar 136 that opens to the distal end 160. As a non-limiting example, the spar interior 164 of the spar may be formed along a corresponding portion of the distal end 160 so that when the spar 136 is received in the socket 154, the spar interior 164 opens to the socket 154. The spar interior 164 may take any suitable shape. As a non-limiting example, the interior surface 162, and therefore the spar interior 164, may be arcuate or otherwise form a dome within the spar 136.

[0062] The spar 136 may include any suitable material. As non-limiting examples, the spar 136 may include a composite material, a foam material, or a polymeric material along a portion of the spar 136. As non-limiting examples, the foam material or the polymeric material may at least partially define the interior surface 162. In the case of a composite material, the spar 136 may be any suitable composite material, such as a 2D or 3D composite material, a laminated skin, a woven or braided composite material, or any other suitable composite material.

[0063] The airfoil assembly 130 also includes a sleeve 166. The sleeve 166 may extend over a corresponding portion of the spar 136. The sleeve 166 may extend through the open top 156 and into the socket 154. The sleeve 166 may be disposed between the spar 136 and the trunnion 134, specifically, radially disposed between the inner surface 152 of the trunnion 134 and the spar 136. The sleeve 166 may extend any suitable axial distance. As a non-limiting example, the sleeve 166 may extend axially beyond the distal end 160 and into the socket 154. As a non-limiting example, the sleeve 166 may terminate at the distal end 160 or terminate axially before the distal end 160. As a non-limiting example, the sleeve 166 may extend along the spar 136 less than, equal to, or greater than the total axial extension of the spar 136. The sleeve 166 may be symmetrical or asymmetrical about the centerline axis 150.

[0064] The sleeve 166 may include a stop 168 that extends radially from the remainder of the sleeve 166 relative to the centerline axis 150. The stop 168 may extend along a corresponding portion of the upper edge 155. The stop 168 may take any suitable shape. As a non-limiting example, when viewed along a plane extending along the centerline axis 150, the stop 168 may include a triangular cross-sectional area. The stop 168 may extend continuously circumferentially around the centerline axis 150. Alternatively, the stop 168 may be segmented so that a plurality of stops 168 are spaced circumferentially around the centerline axis 150. Although the sleeve 166 is shown as including the stop 168, it should be understood that the stop 168 may be excluded.

[0065] The sleeve 166 may be made of any suitable material. As a non-limiting example, the sleeve 166 may include a metal material. The sleeve 166 may include the same or different material as the trunnion 134 or the spar 136. The sleeve 166 may be positioned around the spar 136 and maintained in frictional contact with the spar 136. Alternatively, the sleeve 166 may be coupled to (e.g., welded to, bonded to, fastened to, etc.) the spar 136 or formed integrally with the spar 136. The sleeve 166 may be used to further strengthen the airfoil assembly 130. As a non-limiting example, the spar 136 may be made of a relatively soft composite material. The sleeve 166 may be used to provide additional structural support to the spar 136.

[0066] The balancing insert 170 is disposed along a portion of the airfoil assembly 130. As a non-limiting example, the balancing insert 170 may be disposed along a portion of the stop 168. As a non-limiting example, the balancing insert 170 may extend axially from the stop 168 and axially away from the trunnion 134. Although shown as being formed along the stop 168, it should be understood that the balancing insert 170 may be disposed along any suitable portion of the sleeve 166.

[0067] The balancing insert 170 may extend continuously about the entire circumference of the centerline axis 150. Alternatively, the balancing insert 170 may extend less than the entire circumference of the centerline axis 150, or otherwise be segmented such that the balancing insert 170 includes a plurality of balancing inserts 170 spaced circumferentially about the centerline axis 150. The balancing insert 170 may be coupled to (e.g., welded to, bonded to, fastened to, etc.) or integrally formed with the sleeve 166.

[0068] The balancing insert 170 may include a set of bodies; as a non-limiting example, a first body 172 and a second body 174. For illustrative purposes, the division between the first body 172 and the second body 174 has been shown in phantom. The first body 172 may extend from the sleeve 166. The second body 174 may extend from the first body 172. The first body 172 and the second body 174 may extend a first axial length (Lax1) and a second axial length (Lax2), respectively. The first axial length (Lax1) may be equal to, greater than, or less than the second axial length (Lax2). The first body 172 and the second body 174 may extend a first radial length (Lr1) and a second radial length (Lr2), respectively. The first radial length (Lr1) may be equal to, greater than, or less than the second radial length (Lr2). Although the first body 172 and the second body 174 are both shown as rectangular, it should be understood that the balancing insert 170 may include any suitable cross-sectional area when viewed along a plane extending along the centerline axis 150. In other words, the first body 172 and the second body 174 can each include a corresponding size or mass, wherein the size or mass is different between the first body 172 and the second body 174. It should be understood that the balancing insert 170 can include any number of one or more bodies. It should be understood that the first body 172 and the second body 174 can have different masses from each other or the same mass as each other.

[0069] The balancing insert 170 may be symmetrical or asymmetrical about the centerline axis 150. As shown, the balancing insert 170 is asymmetrical about the centerline axis 150 such that at least one of the first axial length (Lax1), the second axial length (Lax2), the first radial length (Lr1), and the second radial length (Lr2) varies between radial sides of the centerline axis 150. The first radial length (Lr1), the second radial length (Lr2), the first axial height (Lax1), and the second axial height (Lax2) may be constant or non-constant circumferentially around the centerline axis 150. As a non-limiting example, the first radial length (Lr1) and the second radial length (Lr2) may be non-constant, while the first axial length (Lax1) and the second axial length (Lax2) may be constant circumferentially around the centerline axis 150.

[0070] The balancing insert 170 may be made of any suitable material. As non-limiting examples, the balancing insert 170 may be made of a composite material or a metallic material. The material of the balancing insert 170 may include a density different from the density of at least one of the materials of the trunnion 134 , the spar 136 , or the sleeve 166 .

[0071] During operation, the airfoil assembly 130 may experience a working airflow (Fw) ( Figure 2) and the load generated. The airfoil assembly 130 can rotate around the pitch axis (Pax) ( Figure 2 ) rotates and causes the center of mass (CM) ( Figure 2 ) movement. Without the inclusion of the balancing insert 170, the movement of the center of mass (CM) combined with the loads due to the working airflow (Fw) can cause the airfoil assembly 130 to become unbalanced, which in turn causes vibration stresses to be experienced on the airfoil assembly 130. As described herein, it is contemplated that the airfoil assembly 130 may include the balancing insert 170 such that the airfoil assembly 130 remains balanced during all intended uses of the airfoil assembly 130 (e.g., during all intended pitch changes of the airfoil assembly 130 and during movement of the center of mass (CM)). Thus, the balancing insert 170 may be used to limit or otherwise eliminate vibration stresses associated with pitch changes in the airfoil assembly 130.

[0072] The dimensions of the balancing insert 170 (e.g., the first axial length (Lax1), the second axial length (Lax2), the first radial length (Lr1), and the second radial length (Lr2)) may be constant or non-constant circumferentially about the centerline axis 150. As a non-limiting example, in some cases, having dimensions that are non-constant circumferentially about the centerline axis 150 may ensure that the airfoil assembly 130 is circumferentially balanced about the centerline axis 150.

[0073] It is contemplated that the airfoil assembly 130 may be included within a plurality of circumferentially spaced airfoil assemblies. Each of the plurality of circumferentially spaced airfoil assemblies may be coupled to a respective rotatable component, and each airfoil assembly includes a respective center of mass (CM). In this configuration, an unbalanced single airfoil assembly 130 may cause the plurality of circumferentially spaced airfoil assemblies to experience vibration stresses. Therefore, each of the plurality of circumferentially spaced airfoil assemblies 130 may include a respective balancing insert 170 to balance the respective airfoil assembly 130. Alternatively, less than the entirety of the plurality of circumferentially spaced airfoil assemblies (e.g., every other airfoil assembly 130) may include a respective balancing insert 170. The balancing insert 170 may be the same or different between each of the plurality of circumferentially spaced airfoil assemblies. The use of the balancing insert 170 may ensure that the plurality of circumferentially spaced airfoil assemblies remain balanced as the working airflow (Fw) flows through the plurality of circumferentially spaced airfoil assemblies.

[0074] Figure 4 Suitable for use as Figure 21. A schematic cross-sectional view of airfoil assembly 230 of airfoil assembly 130 is shown. Airfoil assembly 230 is similar to airfoil assembly 130; therefore, like parts will be identified with like numerals incremented to the 200 series, and it should be understood that the description of airfoil assembly 130 applies to airfoil assembly 230 unless otherwise noted.

[0075] The airfoil assembly 230 includes a trunnion 234 and a spar 236. The trunnion 234 includes a wall 251 defining a set of interior surfaces 252. The set of interior surfaces 252 at least partially define a socket 254. The trunnion 234 includes an upper edge 255 that defines an open top 256 leading to the socket 254. The spar 236 includes a centerline axis 250. The spar 236 terminates at a distal end 260 within the socket 254. The spar 236 includes an interior surface 262 that at least partially defines a spar interior 264 that defines a void within the spar 236. The airfoil assembly 230 may also include a sleeve 266 extending along the spar 236 and disposed between the spar 236 and the trunnion 234. The sleeve 266 may extend any suitable axial distance. As a non-limiting example, the sleeve 266 may extend axially beyond the distal end 260 and into the socket 254. The sleeve 266 may optionally include a stop 268 that rests on the upper edge 255. It should be appreciated that the sleeve 266 may be omitted from the airfoil assembly 230 such that the spar 236 contacts the trunnion 234 directly.

[0076] The airfoil assembly 230 and the airfoil assembly 130 ( Figure 2 ) in that it includes a balancing insert 270. Balancing insert 270 serves the same functional effect, namely, maintaining a rotating component to which airfoil assembly 230 is coupled in rotational balance when the pitch of airfoil assembly 230 is changed. However, the location of balancing insert 270 is different from balancing insert 170 ( Figure 2 ). Unlike the balancing insert 170, the balancing insert 270 is coupled to the spar 236, rather than being coupled to or disposed along the sleeve 266. In addition, a rib 276 may be disposed within the spar interior 264. The rib 276 may extend between opposing portions of the interior surface 262. Although shown as a rectangular rib, it should be understood that the rib 276 may take any suitable shape. As a non-limiting example, the rib 276 may conform to and extend along corresponding portions of the interior surface 262. The rib 276 may also extend circumferentially along the entirety of the centerline axis 250 or less than the entirety of the centerline axis 250. The rib 276 may be coupled to the spar 236 or otherwise disposed within the spar 236 (e.g., formed integrally with the spar 236).

[0077] The balancing insert 270 may be disposed within the spar interior 264. The balancing insert 270 may extend from the rib 276. The balancing insert 270 may include a set of bodies; as a non-limiting example, a first body 272 and a second body 274. The first body 272 and the second body 274 may extend from respective portions of the rib 276 and into the spar interior 264. It is contemplated that at least a portion of the balancing insert 270 may extend into the socket 254. The first body 272 may be disposed on axially opposite radial sides of the rib 276 relative to the second body 274 or on the same radial side of the rib 276. The balancing insert 270 may extend circumferentially about the entirety of the centerline axis 250 or less than the entirety of the centerline axis 250. The balancing insert 270 may be integrally formed or coupled to the rib 276.

[0078] Since the balancing insert 270 is not disposed along the sleeve 266, the sleeve 266 may be removed from the construction of the airfoil assembly 230. This, in turn, may reduce the weight, complexity, and manufacturing burden of the airfoil assembly 230 as compared to the airfoil assembly 130.

[0079] Figure 5 Is suitable for use as Figure 2 Schematic cross-sectional view of an airfoil assembly 330 of the airfoil assembly 130. The airfoil assembly 330 is similar to the airfoil assemblies 130, 230 ( Figure 4 ); therefore, like parts will be identified with like numbers increased to the 300 series, it being understood that the description of the airfoil assemblies 130, 230 applies to the airfoil assembly 330 unless otherwise indicated.

[0080] The airfoil assembly 330 includes a trunnion 334 and a spar 336. The trunnion 334 includes a wall 351 defining a set of interior surfaces 352. The set of interior surfaces 352 at least partially define a socket 354. The trunnion 334 includes an upper edge 355 that defines an open top 356 leading to the socket 354. The spar 336 includes a centerline axis 350. The spar 336 terminates at a distal end 360 within the socket 354. The spar 336 includes an interior surface 362 that at least partially defines a spar interior 364 that defines a void within the spar 336. The airfoil assembly 330 may also include a sleeve 366 extending along the spar 336 and disposed between the spar 336 and the trunnion 334. The sleeve 366 may extend any suitable axial distance. As a non-limiting example, the sleeve 366 may extend axially beyond the distal end 360 and into the socket 354. The sleeve 366 may optionally include a stop 368 that rests on the upper edge 355. It should be appreciated that the sleeve 366 may be omitted from the airfoil assembly 330 such that the spar 336 contacts the trunnion 334 directly.

[0081] The airfoil assembly 330 and the airfoil assembly 130 ( Figure 2 )、230( Figure 3 ) is similar to the balancing insert 370 in that it includes a balancing insert 370, specifically, similar to the balancing insert 270 ( Figure 4 ) is disposed within the spar interior 364. The balancing insert 370 is located differently from the balancing insert 270 and serves the same functional effect, namely, maintaining a rotating component to which the airfoil assembly 330 is coupled in rotational balance when the pitch of the airfoil assembly 330 changes. The spar 336 also includes ribs 376. The ribs 376 define corresponding portions of the interior surface 362. However, the ribs 376 do not extend across the entire radial extent of the spar interior 364. Instead, the ribs 376 extend radially inwardly from the interior surface 362 and terminate within the spar interior 364 to define a gap (G) between opposing portions of the ribs 376.

[0082] The balancing insert 370 may include a transverse body 378 extending through the gap (G). The balancing insert 370 may include a set of bodies extending from respective portions of the transverse body 378; as non-limiting examples, a first body 372 and a second body 374. For purposes of illustration, the division between the first body 372, the second body 374, and the transverse body 378 has been shown in phantom. The balancing insert 370 may be symmetrical or asymmetrical about the centerline axis 350.

[0083] The balancing insert 370 may include any suitable material. As a non-limiting example, the balancing insert 370 may include a first material having a first density, and the spar 336 may include a second material having a second density. The first density may be greater than the second density. As a non-limiting example, the first material may include a steel or lead material such that the first material is significantly denser than the second material.

[0084] It is contemplated that the balancing insert 370 is defined by a continuous insert for the lateral body 378. As a non-limiting example, the balancing insert 370 may be formed as a disk when viewed along a plane perpendicular to the centerline axis 350. It is contemplated that the balancing insert 370 may be removably coupled to the airfoil assembly 330. As a non-limiting example, the balancing insert 370 may be snap-fit ​​or otherwise coupled to the spar 336 within the spar interior 364.

[0085] The removability of balancing insert 370 may result in increased balance variation of airfoil assemblies 330 as compared to airfoil assemblies 130, 230. For example, each airfoil assembly 330 may be formed without balancing insert 370, but rather with a location (e.g., along spar 336 or sleeve 366) where the balancing insert is coupled to airfoil assembly 330. In other words, spar 336 may be formed identically between airfoil assemblies 330, regardless of where airfoil assembly 330 will be located, e.g. Figure 1 The balancing insert 370 may then be manufactured for the intended implementation of the particular airfoil assembly 330. As a non-limiting example, an airfoil assembly 330 in one location of the turbine engine may require a larger body to properly balance the airfoil assembly 330 than an airfoil assembly 330 disposed in another location of the turbine engine. Thus, the airfoil assembly 330 has a greatly reduced manufacturing burden and increased balance variation compared to the airfoil assemblies 130, 230.

[0086] It should be understood that the airfoil assembly 130 ( Figure 3 )、230( Figure 4 )、330( Figure 5 As a non-limiting example, an airfoil assembly may include a balancing insert 170 formed along a sleeve 166, 266, 366 in combination with another balancing insert 270, 370 disposed along a spar 136, 236, 336.

[0087] Advantages associated with the present disclosure include that the variable pitch airfoil assembly has improved balance compared to conventional variable pitch airfoil assemblies. For example, conventional variable balance assemblies may be formed to maintain balance during a single intended use of the variable pitch airfoil assembly, however, once the pitch changes, the variable pitch airfoil assembly may be unbalanced and cause the variable pitch airfoil assembly to experience vibration stress. Vibration stress will eventually shorten the service life of the variable pitch airfoil assembly. However, as described herein, the variable pitch airfoil assembly includes a balancing insert that is used to properly balance the variable pitch airfoil assembly over a larger pitch range compared to conventional variable pitch airfoil assemblies. The increased balance through the use of a balancing insert ultimately reduces vibration stress, which ultimately increases the service life of the variable pitch airfoil assembly compared to conventional variable pitch airfoil assemblies.

[0088] Additional benefits of the present disclosure include that the variable pitch airfoil assembly has reduced complexity and weight compared to conventional variable pitch airfoil assemblies. For example, a conventional variable pitch assembly may include a complex and large lever arm system connected to a mechanism (e.g., a motor) within a turbine engine to change the pitch of the variable pitch airfoil assembly and to keep the variable pitch airfoil assembly at a desired pitch. Since conventional variable pitch airfoil assemblies do not include a balancing insert, as described herein, conventional variable pitch airfoil assemblies will lose balance when the pitch changes. Therefore, it is necessary to increase the size, strength, and weight of the lever arm system to ensure that conventional variable pitch airfoil assemblies maintain their pitch. However, as described herein, the variable pitch airfoil assembly includes a balancing insert that balances the variable pitch airfoil assembly within a wider range of expected pitches. This in turn means that the lever arm system may be less complex than conventional variable pitch airfoil assemblies to balance the variable pitch airfoil assembly. It is conceivable that the size of the lever arm system may be greatly reduced by using a variable pitch airfoil assembly. This in turn reduces the complexity and weight of the systems required to balance the variable pitch airfoil assembly compared to conventional variable pitch airfoil assemblies.

[0089] To the extent not yet described, the different features and structures of the various embodiments may be used in combination or substituted for each other as desired. The fact that a feature is not shown in all embodiments does not mean that it cannot be shown as such, but is done so for the sake of brevity of description. Therefore, the various features of the different embodiments may be mixed and matched as desired to form new embodiments, whether or not the new embodiments are explicitly described. All combinations or permutations of the features described herein are covered by the present disclosure.

[0090] This written description uses examples to describe the various aspects of the disclosure described herein, including the best mode, and also to enable any person skilled in the art to practice the various aspects of the disclosure, including making and using any device or system and performing any incorporated method. The patentable scope of the various aspects of the disclosure is defined by the claims, and may include other examples that occur to one skilled in the art. These other examples are intended to fall within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims.

[0091] Further aspects are provided by the subject matter of the following clauses:

[0092] A turbine engine comprises: a fan section, a compressor section, a combustion section and a turbine section in a serial flow arrangement and defining a stator section and a rotor section, the rotor section rotating about an engine centerline, wherein the rotor section comprises: a variable pitch airfoil assembly, the variable pitch airfoil assembly having: an airfoil defining an airfoil interior; and a balancing insert disposed along at least a portion of the variable pitch airfoil assembly to maintain balance of the variable pitch airfoil assembly.

[0093] A composite airfoil assembly comprises: a composite airfoil defining an airfoil interior; a composite spar having a centerline axis, the composite spar having a portion located within the airfoil interior and terminating at a distal end, wherein at least a portion of the composite spar has a spar interior defining a void leading to the distal end; a trunnion having a socket extending from an open top, the composite spar extending through the open top and into the socket; and a balancing insert disposed along a portion of the composite airfoil assembly to maintain balance of the composite airfoil assembly.

[0094] A variable pitch airfoil assembly comprises: an airfoil defining an airfoil interior; a spar having a centerline axis, the spar having a portion located within the airfoil interior and terminating at a distal end, wherein at least a portion of the spar has a spar interior defining a void leading to the distal end; a sleeve disposed along at least a portion of the spar; an trunnion having a socket extending from an open top, the spar and the sleeve extending through the open top and into the socket, wherein the sleeve is disposed between the trunnion and the spar; and a balancing insert, the balancing insert being either disposed within the spar interior or disposed along the sleeve.

[0095] A turbine engine comprises: a fan section, a compressor section, a combustion section and a turbine section in a serial flow arrangement and defining a stator section and a rotor section, the rotor section rotating about an engine centerline, wherein the rotor section comprises: a composite variable pitch airfoil assembly, the composite variable pitch airfoil assembly having: a composite airfoil, the composite airfoil defining an airfoil interior; and a balancing insert disposed along at least a portion of the composite variable pitch airfoil assembly to maintain balance of the variable pitch airfoil assembly.

[0096] An airfoil assembly includes: an airfoil defining an airfoil interior; a spar having a centerline axis, the spar having a portion located within the airfoil interior and terminating at a distal end, wherein at least a portion of the spar has a spar interior defining a void leading to the distal end; a trunnion having a socket extending from an open top, the spar extending through the open top and into the socket; and a balancing insert disposed along a portion of the composite airfoil assembly to maintain balance of the variable pitch airfoil assembly.

[0097] A composite variable pitch airfoil assembly, comprising: a composite airfoil, the composite airfoil defining an airfoil interior; a composite spar, the composite spar having a centerline axis, the composite spar having a portion located within the airfoil interior and terminating at a distal end, wherein at least a portion of the composite spar has a spar interior defining a void leading to the distal end; a metal sleeve, the metal sleeve disposed along at least a portion of the composite spar; an ear shaft, the ear shaft having a socket extending from an open top, the composite spar and the sleeve extending through the open top and into the socket, wherein the metal sleeve is disposed between the ear shaft and the spar; and a balancing insert, the balancing insert being either disposed within the spar interior or disposed along the metal sleeve.

[0098] A turbine engine as claimed in any preceding clause, wherein the balancing insert comprises a first body and a second body.

[0099] A turbine engine as claimed in any preceding clause, wherein the first body and the second body have different masses relative to each other.

[0100] A turbine engine according to any preceding clause, wherein the balancing insert comprises a transverse body interconnecting the first body and the second body.

[0101] A turbine engine according to any preceding clause, wherein the variable pitch airfoil assembly further comprises a spar having a centerline axis, the spar having a portion located within the airfoil and terminating at a distal end, wherein at least a portion of the spar has a spar interior surface defining a spar interior; and an trunnion having a socket extending from an open top, the spar extending through the open top and into the socket, wherein the spar interior opens into the socket.

[0102] A turbine engine according to any preceding clause, wherein the balancing insert is any one disposed within the interior of the spar.

[0103] A turbine engine according to any preceding clause, wherein the balancing insert extends between opposing portions of the spar interior surface.

[0104] A turbine engine according to any preceding clause, wherein the balancing insert is disposed within the interior of the spar and extends between opposing portions of the interior surface of the spar.

[0105] A turbine engine as described in any preceding clause, wherein the variable pitch airfoil assembly further comprises a sleeve extending along at least a portion of the spar.

[0106] A turbine engine according to any preceding clause, wherein the trunnion includes an upper edge defining the open top, the sleeve includes a stop formed along a portion of the sleeve and extending radially along a corresponding portion of the upper edge, and the balancing insert is disposed along the stop.

[0107] A turbine engine as described in any preceding clause, wherein the balancing insert is removably coupled to the sleeve or the spar.

[0108] A turbine engine as claimed in any preceding clause, wherein the balancing insert is symmetrical about the centreline axis.

[0109] A turbine engine as claimed in any preceding clause, wherein the balancing insert is asymmetrical about the centreline axis.

[0110] A turbine engine as described in any preceding clause, wherein the balancing insert extends continuously, circumferentially about the centerline axis.

[0111] A turbine engine as claimed in any preceding clause, wherein the variable pitch airfoil assembly is disposed within the fan section.

[0112] A turbine engine according to any preceding clause, wherein the rotor portion includes a plurality of circumferentially spaced variable pitch airfoil assemblies, wherein at least a portion of the variable pitch airfoil assemblies of the plurality of circumferentially spaced variable pitch airfoil assemblies include respective balancing inserts.

[0113] A composite airfoil assembly as described in any preceding clause, wherein the balancing insert comprises any of a composite material or a metallic material.

[0114] A composite airfoil assembly as described in any preceding clause, wherein the balancing insert comprises a metallic material having a density higher than a density of a composite material of the composite spar.

[0115] A composite airfoil assembly as described in any preceding clause, wherein the balancing insert is disposed within the spar interior of the composite spar.

[0116] A composite airfoil assembly according to any preceding clause, further comprising a metallic sleeve disposed between the trunnion and the composite spar, wherein the balancing insert is disposed along a respective portion of the metallic sleeve.

[0117] A turbine engine as in any preceding clause, wherein the first body comprises a first axial length and the second body comprises a second axial length relative to the centerline axis.

[0118] A turbine engine as described in any preceding clause, wherein the first axial length is not equal to the second axial length.

[0119] A turbine engine as described in any preceding clause, wherein the first axial length is greater than or equal to the second axial length.

[0120] A turbine engine as in any preceding clause, wherein at least one of the first axial length or the second axial length is not constant circumferentially about the centerline axis.

[0121] A turbine engine as in any preceding clause, wherein the first body comprises a first radial extent and the second body comprises a second radial extent relative to the centerline axis.

[0122] A turbine engine as in any preceding clause, wherein the first radial length is not equal to the second radial length.

[0123] A turbine engine as claimed in any preceding clause, wherein the first radial length is greater than or equal to the second radial length.

[0124] A turbine engine as in any preceding clause, wherein at least one of said first radial length or said second radial length is not constant circumferentially about said centerline axis.

[0125] A turbine engine as claimed in any preceding clause, wherein the balancing insert is segmented about the centreline axis.

[0126] A turbine engine according to any preceding clause, wherein the airfoil assembly comprises a plurality of balancing inserts provided on both the sleeve and the spar.

Claims

1. A turbine engine, characterized in that: include: a fan section, a compressor section, a combustion section, and a turbine section in a serial flow arrangement and defining a stator section and a rotor section that rotates about an engine centerline, wherein the rotor section includes: A variable pitch airfoil assembly, the variable pitch airfoil assembly comprising: an airfoil defining an airfoil interior; and A balancing insert is disposed along at least a portion of the variable pitch airfoil assembly to maintain balance of the variable pitch airfoil assembly.

2. The turbine engine according to claim 1, characterized in that The balancing insert includes a first body and a second body.

3. The turbine engine according to claim 2, characterized in that: Wherein the first body and the second body have different masses relative to each other.

4. The turbine engine according to claim 2, characterized in that: Wherein the balancing insert includes a lateral body interconnecting the first body and the second body.

5. The turbine engine according to claim 1, characterized in that The variable pitch airfoil assembly further comprises: a spar having a centerline axis, the spar having a portion located within the airfoil interior and terminating at a distal end, wherein at least a portion of the spar has an interior surface defining the spar interior; and A trunnion has a socket extending from the open top, and the spar extends through the open top and into the socket.

6. The turbine engine according to claim 5, characterized in that Wherein the balancing insert is disposed within the interior of the spar and extends between opposing portions of the interior surface.

7. The turbine engine according to claim 5, characterized in that Wherein the variable pitch airfoil assembly further comprises a sleeve extending along at least a portion of the spar.

8. The turbine engine according to claim 7, characterized in that in: The trunnion includes an upper edge defining a top of the opening; The sleeve includes a stopper formed along a portion of the sleeve and extending radially along a corresponding portion of the upper edge; and The balancing insert is disposed along the stop.

9. A composite airfoil assembly, characterized in that: include: a composite airfoil defining an airfoil interior; a composite spar having a centerline axis, the composite spar having a portion located within the airfoil interior and terminating at a distal end, wherein at least a portion of the composite spar has a spar interior defining a void leading to the distal end; a trunnion having a socket extending from an open top, the composite spar extending through the open top and into the socket; and A balancing insert is disposed along a portion of the composite airfoil assembly to maintain balance of the composite airfoil assembly.

10. A variable pitch airfoil assembly, characterized in that: include: an airfoil defining an airfoil interior; a spar having a centerline axis, the spar having a portion located within the airfoil interior and terminating at a distal end, wherein at least a portion of the spar has a spar interior defining a void leading to the distal end; a sleeve disposed along at least a portion of the spar; a trunnion having a socket extending from an open top, the spar and the sleeve extending through the open top and into the socket, wherein the sleeve is disposed between the trunnion and the spar; and A balancing insert is disposed within the interior of the spar or along the sleeve.

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