Lever counterweight feathering system

Abstract

A fan assembly for a gas turbine engine includes a fan disk, a trunnion, fan blades, and a counterweight assembly. The fan disk is configured to rotate about an axial centerline of the gas turbine engine when installed in the gas turbine engine. The trunnion is mounted to the fan disk and defines a slot extending through a portion of the trunnion. The fan blades define a pitch axis and are rotatably attached to the fan disk about their pitch axis by the trunnion. The counterweight assembly includes a link arm extending to the trunnion and an engagement device mounted to the link arm, the engagement device being disposed to move through the slot of the trunnion.

Description

Technical Field

[0001] This disclosure generally relates to gas turbine engines, and more specifically, to gas turbine engines with variable pitch fans. Background Technology

[0002] Gas turbine engines typically consist of a turbine and a rotor assembly. Gas turbine engines, such as turbofan engines, are used for aircraft propulsion. In the case of turbofan engines, the rotor assembly can be constructed as a fan assembly.

[0003] In some gas turbine engines, variable pitch fan assemblies are used to control the pitch of the fan blades. As the pitch of the fan blades is adjusted, the amount of drag on the fan blades is changed. In existing variable pitch fan assemblies, in certain failure modes where the ability to control the fan blade pitch is lost, the natural centrifugal torsional torque of the fan blades will cause the fan blades to rotate to a high-drag (e.g., fine) position. In existing engine designs, there is limited space to implement a feathering system to address the centrifugal torque problem that leads to undesirable blade rotation. Attached Figure Description

[0004] This specification sets forth a complete and enabling description of the present disclosure to a person skilled in the art, including its best mode, with reference to the accompanying drawings, wherein:

[0005] Figure 1 This is a schematic cross-sectional view of an exemplary gas turbine engine according to various embodiments of this subject matter.

[0006] Figure 2 This is a three-dimensional detached view of a fan hub including multiple trunnions and a counterweight assembly, according to an exemplary aspect of this disclosure.

[0007] Figure 3 This is a side view of the rotor blades, trunnions, and counterweight assembly according to an exemplary aspect of this disclosure.

[0008] Figure 4 This is a separate view of the trunnion and connecting arm according to an exemplary aspect of this disclosure, showing the engagement device of the connecting arm separated from the trunnion.

[0009] Figure 5 This is a separate view of the trunnion and connecting arm according to an exemplary aspect of this disclosure, showing the engagement device of the connecting arm engaging with the slot of the trunnion.

[0010] Figure 6 This is a perspective view of the trunnion and counterweight assembly according to an exemplary aspect of this disclosure.

[0011] Figure 7 This is a front view of the trunnion and counterweight assembly according to an exemplary aspect of this disclosure.

[0012] Figure 8 This is a simplified perspective view of the trunnion and the first counterweight assembly according to an exemplary aspect of this disclosure.

[0013] Figure 9 This is a simplified perspective view of the trunnion and second counterweight assembly according to an exemplary aspect of this disclosure.

[0014] Figure 10 This is a simplified perspective view of the trunnion and third counterweight assembly according to an exemplary aspect of this disclosure.

[0015] Figure 11 This is a simplified perspective view of the trunnion and the fourth counterweight assembly according to an exemplary aspect of this disclosure.

[0016] Figure 12 This is a simplified side view of the trunnion and counterweight assembly attached to a linear actuator according to an exemplary aspect of this disclosure.

[0017] Figure 13 This is a bottom view of a trunnion in a first angular position according to an exemplary aspect of this disclosure, the trunnion having a slot and an engagement device for a counterweight assembly disposed in the slot.

[0018] Figure 14 This is a bottom view of the trunnion in a second corner position according to an exemplary aspect of this disclosure, and shows the engagement device of the counterweight assembly in contact with the stop.

[0019] Figure 15 This is a bottom view of another trunnion having two slots with damper elements, according to an exemplary aspect of this disclosure. Detailed Implementation

[0020] Reference will now be made in detail to the present embodiments of this disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerals and letter reference numerals to denote features in the drawings. Similar or analogous reference numerals in the drawings and description have been used to denote similar or analogous portions of this disclosure.

[0021] The term “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or superior to other implementations. Furthermore, unless explicitly stated otherwise, all embodiments described herein should be considered exemplary.

[0022] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components. The terms “front” and “rear” refer to relative positions within a gas turbine engine or vehicle and to the normal operating posture of the gas turbine engine or vehicle. For example, for a gas turbine engine, “front” refers to a position closer to the engine inlet, while “rear” refers to a position closer to the engine nozzle or exhaust port. The terms “upstream” and “downstream” refer to relative directions of fluid flow in a fluid path. For example, “upstream” refers to the direction from which the fluid flows, while “downstream” refers to the direction in which the fluid flows. Unless otherwise specified herein, the terms “connected,” “fixed,” “attached to,” etc., refer both to a direct connection, fixation, or attachment and to an indirect connection, fixation, or attachment via one or more intermediate components or features. The singular forms “a,” “an,” and “described” include plural references unless the context clearly specifies otherwise.

[0023] The approximate language used throughout this specification and claims is applied to modify any quantitative expression that allows for variation without altering its associated essential function. Therefore, values ​​modified by one or more terms such as “about,” “approximately,” and “substantially” are not limited to specified exact values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value, or the precision of the method or machine used to construct or manufacture the component and / or system. For example, approximate language may refer to margins of 1%, 2%, 4%, 10%, 15%, or 20%. These approximate margins may apply to a single value, to either or both endpoints of a defined numerical range, and / or to the margin of the range between endpoints.

[0024] Throughout this specification and claims, scope limitations are combined and interchanged, and unless the context or language otherwise indicates otherwise, such scopes are identified and include all subscopes contained herein. For example, all scopes disclosed herein include endpoints, and endpoints may be combined independently of each other.

[0025] This disclosure generally relates to a passive feathering system for the fan section of a gas turbine engine. In particular, aspects of this disclosure relate to a trunnion having a disc with slots extending on or within the disc. The passive feathering system, or more precisely, the linkage arm of the counterweight assembly, includes an engagement device configured to engage the slot, thereby defining a range of relative movement with respect to the slot. In this way, the counterweight assembly can be moved relative to the trunnion for the range of movement and can then engage the trunnion outside the range of movement. This configuration allows the trunnion to move relative to the counterweight assembly during certain operations (e.g., normal operating speeds) and further allows the counterweight assembly to engage the trunnion to move the fan blades to a desired pitch angle during other operations (e.g., faulty operating speeds).

[0026] Referring now to the accompanying drawings, where the same numbers represent the same elements throughout all the drawings. Figure 1 This is a schematic cross-sectional view of a gas turbine engine 10 according to various embodiments of the subject matter.

[0027] More specifically, for Figure 1 In one embodiment, the gas turbine engine is a high-bypass turbofan jet engine, referred to herein as "gas turbine engine 10". Figure 1 As shown, the gas turbine engine 10 defines an axial direction A (extending parallel to an axial centerline 12 provided for reference) and a radial direction R. Typically, the gas turbine engine 10 includes a fan section 14 and a core turbine engine 16 disposed downstream of the fan section 14.

[0028] The core turbine engine 16 described herein generally includes a substantially tubular outer casing 18 defining an annular inlet 20. The casing 18 surrounds, in a series flow relationship, a compressor section comprising a turbocharger or low-pressure (“LP”) compressor 22 and a high-pressure (“HP”) compressor 24; a combustion section 26; a turbine section comprising a high-pressure (“HP”) turbine 28 and a low-pressure (“LP”) turbine 30; and an exhaust nozzle section 32. In one example, the LP compressor 22 and the HP compressor 24 may be collectively referred to as the compressor section. In another example, the HP turbine 28 and the LP turbine 30 may be collectively referred to as the turbine section. A high-pressure (“HP”) shaft or spool 34 drives the HP turbine 28 to the HP compressor 24. A low-pressure (“LP”) shaft or spool 36 drives the LP turbine 30 to the LP compressor 22. The compressor section (e.g., LP compressor 22 and HP compressor 24), combustion section 26, turbine section (e.g., HP turbine 28 and LP turbine 30) and injection exhaust nozzle section 32 together define the core airflow path 37.

[0029] In the depicted embodiment, fan section 14 includes a variable-pitch fan 38 having a plurality of fan blades 40 spaced apart and coupled to disk 42. In one example, the variable-pitch fan 38 may be referred to as a fan assembly. In another example, disk 42 may be referred to as a fan disk. Disk 42 is configured to rotate about an axial centerline 12 of gas turbine engine 10 when mounted in gas turbine engine 10. As shown, fan blades 40 extend outward from disk 42 generally in a radial direction R. Each fan blade 40 is rotatable relative to disk 42 about a pitch axis P, as the fan blades 40 are operably coupled to suitable trunnions 44, which are configured to collectively and uniformly change the pitch of the fan blades 40. The fan blades 40, disk 42, and trunnions 44 can be rotated together about an axial centerline 12 via an LP shaft or spool 36 across a power gearbox 46. The power gearbox 46 includes a plurality of gears for regulating the rotational speed of fan 38 relative to LP shaft or spool 36 to a more efficient fan speed.

[0030] Still referencing Figure 1 In an exemplary embodiment, the disk 42 is covered by a rotatable front hub 48 having an aerodynamic profile to facilitate airflow through a plurality of fan blades 40. Additionally, the fan section 14 includes an annular fan housing or outer nacelle 50 circumferentially surrounding at least a portion of the variable-pitch fan 38 and / or the core turbine engine 16. It should be understood that the nacelle 50 may be configured to be supported relative to the core turbine engine 16 by a plurality of circumferentially spaced outlet guide vanes 52. Furthermore, a downstream section 54 of the nacelle 50 may extend above an external portion of the core turbine engine 16 to define a bypass airflow passage 56 therebetween.

[0031] During operation of the gas turbine engine 10, a volume of air 58 enters the gas turbine engine 10 through the nacelle 50 and / or the relevant inlet 60 of the fan section 14. As the volume of air 58 passes through the fan blades 40, a first portion of the air 58, as indicated by arrow 62, is directed or directed into the bypass airflow passage 56, and a second portion of the air 58, as indicated by arrow 64, is directed or directed into the core airflow path 37, or more specifically, into the LP compressor 22. The ratio between the first portion 62 and the second portion 64 of air is commonly referred to as the bypass ratio. The pressure of the second portion 64 of air then increases as it is directed through the high-pressure (HP) compressor 24 and into the combustion section 26, where the second portion 64 of air is mixed with fuel and burned to provide combustion gases 66.

[0032] Combustion gas 66 is guided through HP turbine 28, where a portion of the thermal and / or kinetic energy from the combustion gas 66 is extracted via a sequential stage of HP turbine stator blades 68 connected to housing 18 and HP turbine rotor blades 70 connected to HP shaft or spool 34, thus causing HP shaft or spool 34 to rotate, thereby supporting the operation of HP compressor 24. Combustion gas 66 is then guided through LP turbine 30, where a second portion of the thermal and kinetic energy is extracted from the combustion gas 66 via a sequential stage of LP turbine stator blades 72 connected to housing 18 and LP turbine rotor blades 74 connected to LP shaft or spool 36, thus causing LP shaft or spool 36 to rotate, thereby supporting the operation of LP compressor 22 and / or fan 38.

[0033] Combustion gas 66 is then directed through the injection exhaust nozzle section 32 of the core turbine engine 16 to provide propulsive thrust. Simultaneously, as the first portion of air 62 is directed through the bypass airflow passage 56 before being exhausted from the fan nozzle exhaust section 76 of the gas turbine engine 10, the pressure of the first portion of air 62 increases significantly, also providing propulsive thrust. The HP turbine 28, LP turbine 30, and injection exhaust nozzle section 32 at least partially define the hot gas path 78 for directing combustion gas 66 through the core turbine engine 16.

[0034] However, it should be understood that Figure 1 The exemplary gas turbine engine 10 depicted herein is merely an example, and in other exemplary embodiments, the gas turbine engine 10 may have any other suitable configuration. It should also be understood that aspects of this disclosure may be incorporated into any other suitable gas turbine engine in other exemplary embodiments. For example, aspects of this disclosure may be incorporated into, for example, a turboprop engine in other exemplary embodiments.

[0035] During operation of the gas turbine engine 10, a failure condition may occur, including the loss of controllable pitch (e.g., rotational degrees) of one or more fan blades 40. In this situation, the natural centrifugal torsional moment of the blade geometry will naturally rotate the fan blades 40 to a high-drag (e.g., fine) position without corrective action. To counteract this natural centrifugal torsional moment of the fan blades 40, a feathering device is used to correct the pitch change of the fan blades 40. As discussed herein, "feeding" is a safety feature required to reduce wind-wear drag of the variable-pitch fan 38 in the event of a failure condition in which the pitch control capability of one or more fan blades 40 is lost.

[0036] Now for reference Figure 2 , Figure 2 This is a three-dimensional detached view of a variable pitch fan 38 having trunnion 44 and counterweight assembly 80 according to an exemplary aspect of this disclosure. Figure 2 The diagram shows the axial centerline 12, the variable pitch fan 38, the pitch axis P, the disk 42, the trunnion 44, and the counterweight assembly 80 (each counterweight assembly 80 includes a linkage arm 82, a lever arm 84, a hinge 86, and a counterweight 88). Figure 2 In the example shown, fan blade 40 is omitted for clarity. Figure 2 In the example, the downstream direction is shown as from left to right. In another example, the downstream direction could be from right to left, such as... Figure 2 As shown.

[0037] Each trunnion 44 comprises a generally tubular shape and has a lip or collar at the end of the trunnion 44 closest to the disc 42. In this example, each trunnion 44 is coupled to the fan blade 40. Figure 1 One of the fan blades 40 (as shown in the diagram) is configured such that each fan blade 40 is rotatable relative to the disk 42 about its respective pitch axis P. Each trunnion 44 is configured to drive the rotation of one of the fan blades 40.

[0038] Each counterweight assembly 80 is operatively coupled to one of the trunnions 44. In this example, the counterweight assemblies 80 are evenly distributed along the circumference of the disk 42, wherein the number of counterweight assemblies 80 matches the number of trunnions 44. The counterweight assemblies 80 are configured to drive the trunnions 44 to rotate in response to centrifugal force experienced by the counterweights 88.

[0039] In the illustrated embodiment, the linkage arm 82 and lever arm 84 are elongated solid material parts. In one example, the linkage arm 82 and lever arm 84 may comprise a rod. The linkage arm 82 is configured to be coupled to the trunnion 44. Each linkage arm 82 is connected to one of the trunnions 44 and one of the lever arms 84 and extends between them. The linkage arm 82 transmits motion and torque from the lever arm 84 to the trunnion 44. In this way, the linkage arm 82 is configured to drive the trunnion 44 to rotate relative to the disc 42.

[0040] Each lever arm 84 is connected to one of the link arms 82 and one of the counterweights 88 and extends between them. The connection point of the lever arm 84 with the hinge 86 includes a pivot (or pivot point). In one example, the lever arm 84 may be pivotally or rotatably connected to the link arm 82. In other words, the lever arm 84 and the hinge 86 define a pivot connection point. In another example, the lever arm 84 may be fixedly connected to or connected to the link arm 82. The lever arm 84 is configured to transmit movement / motion (e.g., angular motion / rotation) of the counterweight 88 to the link arm 82.

[0041] In this example, hinge 86 is a solid material component configured to allow another component to rotate about a pivot point of hinge 86. Each hinge 86 is pivotally connected to one of the lever arms 84. For example, each of the lever arms 84 is configured to rotate about a point of connection between one of the lever arms 84 and one of the hinges 86. The point of connection between the lever arm 84 and the hinge 86 includes a pivot. Hinge 86 provides a pivot about which the lever arm 84 rotates to transmit rotation from the lever arm 84 to the link arm 82.

[0042] The counterweight 88 is a weight or a solid material component with mass. In this example, the shape of the counterweight 88 includes a disc. In other examples, the shape of the counterweight 88 may include a sphere, an ellipsoid, a corner portion of a flat ring, a parallelogram, or other geometric shapes. Each counterweight 88 is mounted to one end of one of the lever arms 84 at the end opposite to the hinge 86. Each counterweight 88 is mounted to one of the lever arms 84 at a location spaced apart from one of the hinges 86. Each counterweight 88 is configured to move in response to changes (e.g., decreases or increases) in the centrifugal load applied to the counterweight 88 during operation of the variable pitch fan 38. The counterweight 88 is configured to provide an increased force on the trunnion 44 in response to an increased centrifugal load applied to the counterweight 88 during operation of the variable pitch fan 38.

[0043] For example, during certain operating (e.g., failure) modes of the gas turbine engine 10, the fan blades 40 of the variable pitch fan 38 (such as...) Figure 1 The fan blade 40 (shown) will rotate in response to a natural centrifugal torsional moment. This rotation causes the fan blade 40 to rotate to an undesirable high-drag (e.g., fine) position. In response to the centrifugal force experienced by the counterweight 88, the counterweights 88 transmit the torque they generate to the trunnion 44 (via lever arm 84, hinge 86, and connecting rod arm 82) to overcome this centrifugal torsional moment and rotate the fan blade 40 to a low-drag or feathering (e.g., coarse) position. The mass, density, and shape of the counterweight 88 can be adjusted and / or customized based on the desired performance characteristics of the counterweight assembly 80. In this example, the individual counterweight assembly 80 for each fan blade 40 serves to minimize combined failure modes.

[0044] As proposed, the counterweight assembly 80 introduces sufficient torque to the trunnion axis of each blade to overcome the centrifugal torsional moment and rotate each fan blade 40 to a low-drag or feathering (e.g., coarse) position. Furthermore, as... Figure 2 As shown, the counterweight assembly 80 is configured such that each counterweight 88 is not obstructed by adjacent counterweights 88. As will be discussed with respect to the following figures, Figure 2 The counterweight assembly is shown positioned in such a way that there is no spacing constraint between the fan blades 40 or between adjacent counterweight assemblies 80, thereby prohibiting or preventing the movement / motion of the counterweight 88 during operation.

[0045] In some configurations, the weight can be mounted above the disk, off-center from the blades. However, in configurations with low radius-to-weight ratios and taller fan blades, such a configuration is not practically feasible, and the lack of mechanical advantage could result in a greater weight requirement. As will be discussed with regard to the following figures, the counterweight assembly 80 offers a high degree of mechanical advantage because the pivot point of hinge 86 is positioned at a lower radial location along lever arm 84. Due to this high mechanical advantage, the increased length of lever arm 84 helps to minimize the overall weight of the counterweight 88 required to achieve the feathering capability needed to achieve the counterweight assembly 80.

[0046] Now for reference Figure 3 , Figure 3 This is a side view of a counterweight assembly 80 attached to the trunnion 44 according to an exemplary aspect of this disclosure. Figure 3 The diagram shows the pitch axis P, fan blades 40, disk 42, trunnion 44 (having a body 90, disk 92', and engagement device 94), counterweight assembly 80 (having a connecting arm 82, connection point 96, lever arm 84 (including a first lever portion 98 and a second lever portion 100), hinge 86 (including a first hinge portion 102, a second hinge portion 104, and a pivot 106), counterweight 88), and bearing assembly 108 (having a sleeve 110 and a ball bearing 112). Figure 3 In the example shown, the disc 42, sleeve 110, and ball bearing 112 are shown in cross-section.

[0047] The main body 90 is a solid material tube. The main body 90 is mechanically connected to the fan blade 40 and mounted to the disc 92'. The main body 90 receives torque from the disc 92' and transmits it to the fan blade 40. The disc 92' is a solid material extension extending radially outward from the main body 90. In this example, the disc 92' is a solid material ring or disc that is approximately coaxial with the pitch axis P. Here, the disc 92' is... Figure 2 The difference between the corresponding components shown is that the disc 92' is shown extending a full 360° around the trunnion 44. The disc 92' is connected to the body 90 and the engagement device 94 and extends between them. The disc 92' receives force from the engagement device 94 and transmits that force to the body 90. In one example, the disc 92' is coupled to the body 90 or is integral with the body 90.

[0048] However, it will be understood that in other exemplary embodiments, the disc 92' may have any other suitable geometry that allows for the functionality discussed herein. For example, the disc 92' may not be a complete 360° disc, but may only extend partially around the body 90 of the trunnion 44.

[0049] The engagement device 94 is a pin comprising a short rod of solid material extending in a direction parallel to the axial direction of the body 90 (and parallel to the pitch axis P of the fan blade 40). In this example, the engagement device 94 is fixed to one end of the linkage arm 82. The engagement device 94 is rotatably connected to the disc 92' and connects the linkage arm 82 to the disc 92' of the trunnion 44. The engagement device 94 receives a force from the first lever portion 98 and transmits that force to the disc 92' of the trunnion 44.

[0050] The first lever portion 98 and the second lever portion 100 of the lever arm 84 are flat, elongated solid material pieces. In this example, the first lever portion 98 and the second lever portion 100 are shown misaligned and at an angle θ to each other. LV Setting. Specifically, the angle θ between the first lever portion 98 and the second lever portion 100. LV It is shown as approximately 90°. In other embodiments, the angle θ LV It can be any angle, depending on optimal design considerations. The first lever section 98 is at an angle θ. LV A second lever portion 100 is connected to the first lever portion 98 and the counterweight 88, and extends between the first lever portion 98 and the counterweight 88. The second lever portion 100 transmits torque from the counterweight 88 to the first lever portion 98. For example, when the counterweight 88 is subjected to centrifugal force, the second lever portion 100 is pushed along path 114, causing the first lever portion 98 to rotate in response to the rotation of the second lever portion 100. The mechanical advantage of the lever arm 84 arises from the length difference between the first lever portion 98 and the second lever portion 100.

[0051] In the illustrated embodiment, the first hinge portion 102 and the second hinge portion 104 are elongated solid material parts. The first hinge portion 102 is mounted to the disk 42 and extends between the disk 42 and the second hinge portion 104. The first hinge portion 102 secures the hinge 86 to the disk 42. The second hinge portion 104 is pivotally connected to the lever arm 84 and extends between the pivot 106 and the first hinge portion 102. The second hinge portion 104 accommodates the pivot 106 about which the lever arm 84 rotates.

[0052] Pivot 106 is a fulcrum or point of rotation. In this example, lever arm 84 is configured to pivot about pivot 106 of hinge 86. Pivot 106 is located in the second hinge portion 104 of hinge 86. Pivot 106 is connected to and rotatably attaches lever arm 84 to hinge 86. During operation, lever arm 84 rotates about pivot 106, causing counterweight 88 to travel along path 114. In this example, path 114 is shown as an arc-shaped path including a partial arc. Similarly, the connection point between link arm 82 and the first lever portion 98 of lever arm 84 travels along path 116. In this example, path 116 is shown as also including a partial arc. Pivot 106 serves as a fulcrum for lever arm 84 to rotate about it relative to hinge 86.

[0053] The bearing assembly 108 is a set of components used to enable relative rotation between two or more components. The bearing assembly 108 is disposed in and mounted to the disc 42. When the counterweight assembly 80 drives the trunnion 44 to rotate, the bearing assembly 108 enables relative rotation between the disc 42 and the sleeve 110.

[0054] Sleeve 110 is typically a solid tubular or truncated conical structure. Sleeve 110 is mounted in the opening of disc 42. Sleeve 110 provides a structural interface between trunnion 44 and fan blade 40. Ball bearing 112 is a rolling element bearing. Ball bearing 112 is disposed between sleeve 110 and disc 42. Ball bearing 112 rotates relative to sleeve 110 and disc 42, allowing fan blade 40 and trunnion 44 to rotate relative to disc 42.

[0055] As described above, due to the mechanical advantage of lever arm 84 when it rotates about pivot 106 of hinge 86, counterweight assembly 80 provides a great deal of effective mechanical advantage in driving the rotation of trunnion 44 and counterweight assembly 80.

[0056] Now for reference Figure 4 , Figure 4 This is a separate view of the trunnion 44 and the connecting arm 82 according to an exemplary aspect of this disclosure, showing the engagement device 94 separate from the trunnion 44.

[0057] Here, the trunnion 44 is shown as including a body 90 and a disc 92' with a slot 93. The disc 92' is an annular ring extending radially outward from the body 90.

[0058] The slot 93 is an opening or channel provided in and defined by the disc 92' of the trunnion 44. In this example, the slot 93 is an arcuate cut in the disc 92'. The slot 93 is in the axial direction of the trunnion 44 (e.g., as shown in the image). Figure 4(As shown above and below) A portion of the disc 92' cuts into and passes through the trunnion 44. In one example, the slot 93 extends all the way through the disc 92'. In this example, the shape of the slot 93 includes an arcuate or bow-shaped opening extending approximately 60° (e.g., 1 radian) relative to (e.g., around) the pitch axis P. In another example, the slot 93 may extend less than or greater than 60° (e.g., greater than or less than 1 radian). For example, in yet another example, the slot 93 may extend at least about 10°, such as at least about 15°, such as at least about 30°, such as at least about 45°, such as at most about 180°, such as at most about 150°, such as at most about 120°, such as at most about 90°. In another example, the slot 93 may be defined and disposed within a disc at the end of the body 90 opposite to the disc 92'.

[0059] In this example, the engagement device 94 is attached and mounted to the link arm 82. In one example, the engagement device 94 may be fixed to the link arm 82 such that the engagement device 92' is stationary relative to the link arm 82. In another example, the engagement device 94 may rotate relative to the link arm 82. In this example, as the engagement device 94 moves through the slot 93, the slot 93 allows the link arm 82 to drive the engagement device 94 without causing the trunnion 44 to move.

[0060] Figure 5 The trunnion 44 and the connecting arm 82, according to an exemplary aspect of this disclosure, are shown in a separate view, illustrating the engagement device 94 engaging with the slot 93.

[0061] Here, the engaging device 94 is inserted and passes through the slot 93 to engage the connecting arm 82 with the trunnion 44. The engaging device 94 is disposed in the slot 93 and configured to move along and through the slot 93. In other words, the engaging device 94 engages with the slot 93 and is configured to slide through the slot 93.

[0062] In this example, retaining element 95 is attached to one end of engaging device 94. Retaining element 95 is a flat disk. In other examples, retaining element 95 may take another form and / or include a different shape than a flat disk. Retaining element 95 is configured to hold engaging device in slot 93 while also allowing engaging device 94 to slide or travel through slot 93.

[0063] It will be understood that, although for the depicted embodiment, slot 93 extends fully through disk 92' and engagement device 94 is configured to extend fully through slot 93, other configurations are contemplated in other exemplary embodiments. For example, in other embodiments, slot 93 may have a lateral geometry, and engagement device may be a structure with a complementary lateral geometry to allow engagement device movement through slot 93. Additionally or alternatively, slot 93 may be a structure extending from the surface of disk 92' (e.g., a track), and engagement device may be a structure configured to engage slot 93 / track.

[0064] Now for reference Figure 6 , Figure 6 This is a perspective view of the trunnion 44 and the counterweight assembly 80 according to an exemplary aspect of this disclosure. Figure 6 The pitch axis P, trunnion 44 (with body 90, disk 92' with slot 93 and engagement device 94), counterweight assembly 80 (with linkage arm 82, lever arm 84, hinge 86 and counterweight 88), path 114, path 116, disk rotation direction 118 and rotation direction 120 are shown.

[0065] here, Figure 6 The rotation direction 118 of the disc 92' including the trunnion 44 and the rotation direction 120 of the connecting rod arm 82. The rotation direction 118 of the disc 92' shows the rotational motion of the disc 92' when the counterweight assembly 80 drives the trunnion 44 to rotate.

[0066] The rotation direction 120 of the linkage arm 82 shows the path of motion of the linkage arm 82 as it rotates relative to the connection point between the linkage arm 82 and the lever arm 84. This rotation direction 120 of the linkage arm 82 allows it to move together with the engagement device 94 as the disc 92' of the trunnion 44 rotates in the disc rotation direction 118. Thus, the ability of the linkage arm 82 to rotate in the rotation direction 120 allows the trunnion 44 to rotate about the pitch axis P, while the lever arm 84 of the counterweight assembly 80 rotates along a single plane (see, for example...). Figure 7 ).

[0067] Now for reference Figure 7 , Figure 7 This is a front view of the trunnion 44 and the counterweight assembly 80 in the axial direction 122, according to an exemplary aspect of this disclosure. Figure 7 The pitch axis P, trunnion 44 (having a body 90, a disc 92' with a slot 93 and a coupling device 94) are shown, as well as the counterweight assembly 80 (having a connecting arm 82, a lever arm 84, a hinge 86 and a counterweight 88), the axial direction 122, and the plane P of the counterweight assembly 80 are shown. CW .

[0068] The axial direction 122 is oriented relative to the axial centerline 12 of the gas turbine engine 10 (see example). Figure 1-2 The alignment direction. Figure 7 In this example, the axial direction 122 is oriented for entering and exiting the page. The axial direction 122 points relative to the downstream and upstream directions of the gas turbine engine 10 (as shown in the image below). Figure 7 (As shown in the instructions for entering and leaving the page).

[0069] Plane P CW Plane P is the plane along which the lever arm 84, hinge 86, and counterweight 88 are aligned. CW It also refers to the translation plane, along which the lever arm 84 and the counterweight 88 move or translate during the operation of the counterweight assembly 80. For example, regarding Figure 3 and 6 The path 114 of the counterweight 88 shown in -7, plane P CW It is the plane along which path 114 travels and aligns. Figure 7 Plane P shown in the figure CW The way the page extends in and out is the same, and path 114 is aligned in the same way as the page.

[0070] In this example, plane P CW Aligned parallel to the axial direction 122, making plane P CW Extend into and out of the page. In one example, the plane P of the counterweight component 80... CW With respect to the axial centerline 12 of the gas turbine engine 10 (for example, see...) Figure 2 The axial centerline 12 in the drawing intersects.

[0071] Here Figure 7 In the middle, plane P CW The direction of disk rotation 118 is shown as an offset from the pitch axis P to illustrate disk 92'. Plane P CW It is also shown as misaligned and / or non-parallel to the pitch axis P of the trunnion 44, and via an extension to the fan blade 40 corresponding to the trunnion 44 (for clarity, from...). Figure 7 (The text is incomplete and appears to be a fragment of a larger document. A possible interpretation is:) The plane P is misaligned. CW It is not aligned with the pitch axis P of the fan blades 40 along the axial direction of the disk 42. In other words, plane P CW Extending at a certain angle relative to the pitch axis P, such that plane P... CW Finally, it intersects and crosses the pitch axis P. Because the linkage arm 82 can move in and out of the page when the lever arm 84 drives the linkage arm 82 into the page, it pushes the engagement device 94 and causes the disk 92' to rotate the main body 90 around the pitch axis P, the pitch axis P and the plane P CWThe misalignment and offset between them eliminate the spatial constraints of the counterweight assembly 80 between adjacent fan blades 40. During this operation of the counterweight assembly 80, the components of the counterweight assembly 80 (e.g., linkage arm 82, lever arm 84, hinge 86, and counterweight 88) operate without contacting the components of adjacent counterweight assemblies 80 disposed around the disk 42 (see, for example...). Figure 2 ).

[0072] In other words, the misalignment or offset construction of the counterweight assembly 80 relative to the pitch axis P also allows for a high mechanical advantage system by positioning the components of the counterweight assembly 80 in such a way that the spatial constraints on the spacing between adjacent fan blades 40 are less.

[0073] Now for reference Figure 8 , Figure 8 This is a simplified perspective view of the fan blade 40, trunnion 44, and counterweight assembly 80, shown in a first configuration according to an exemplary aspect of this disclosure. Figure 8 The diagram shows the pitch axis P, fan blades 40, trunnion 44 (having a body 90, a disc 92' with a slot 93, and a coupling device 94), counterweight assembly 80 (having a linkage arm 82, connection point 96, lever arm 84 (including a first lever portion 98 and a second lever portion 100), hinge 86, counterweight 88, sleeve 110, path 114 of lever arm 84, disc rotation direction 118 of disc 92', connection point 124, connection point 126, and force F. C .exist Figure 8 In the example shown, the first lever portion 98 includes a first length L1, and the lever arm 84 includes a second length L2.

[0074] exist Figure 8 In the diagram, hinge 86 is shown in a simplified triangular view, clearly illustrating its pivot or fulcrum function. In this example, hinge 86 is connected to lever arm 84 at one end (e.g., at connection point 126).

[0075] The first length L1 is the length of the first lever portion 98 of the lever arm 84. The second length L2 is the length of the lever arm 84. In this example, the first lever portion 98 and the second lever portion 100 are shown aligned with each other. In such an example, the angle θ LV Equal to 180° (and) Figure 3 Angle θ in LV (Approximately equal to 90°). In other examples, the angle θ LV The range can be from 0° to 90°, from 90° to 180°, or from 180° to 360°.

[0076] In this example, the second length L2 of the lever arm 84 is greater than the first length L1 of the first lever portion 98. This gives the lever arm 84 a mechanical advantage because the counterweight 88 travels a greater distance along path 114 than the connecting point 124 (and the link arm 82) does. As the connecting point 124 travels in response to the rotation of the lever arm 84, the link arm 82 transmits motion from the lever arm 84 to the engagement device 94, which in turn transmits torque to the trunnion 44.

[0077] Another aspect of this example is that the lever arm 84 is connected to the hinge 86 at connection point 126 located at the distal end of the first lever portion 98 (as shown in the diagram where the hinge 86 is connected to the point where the first lever portion 98 is connected to the second lever portion 100). Figure 3 and Figure 6 Conversely). Similarly, in Figure 8 In the example shown, lever arm 84 is connected to link arm 82 at connection point 124, which is located where the first lever portion 98 and the second lever portion 100 meet (as shown in the example where lever arm 84 is connected to link arm 82 at the distal end of the first lever portion 98). Figure 3 and Figure 6 (Conversely). Since connection points 124 and 126 include a spherical bearing linkage, motion can be transmitted from the counterweight assembly 80 to the trunnion 44 without the use of gears.

[0078] Connection point 124 is the connection point between link arm 82 and lever arm 84. Connection point 126 is the connection point between lever arm 84 and hinge 86. In this example, connection points 124 and 126 may include spherical bearings to allow circumferential movement of link arm 82 and lever arm 84.

[0079] Force F C During the operation of the gas turbine engine 10, with the disc 42 ( Figure 2 The centrifugal force is applied to the counterweight 88 as it rotates (as shown). For example, the counterweight 88 is configured to respond to the variable pitch fan 38 (see example...) Figure 1 The force F applied to the counterweight 88 during operation C It moves due to changes in the load (e.g., changes in centrifugal load).

[0080] Figure 8 The embodiment shown provides an example of a first construction of a counterweight assembly 80 having a trunnion 44.

[0081] Now for reference Figure 9 , Figure 9 This is a simplified perspective view of the fan blade 40, trunnion 44, and counterweight assembly 80, shown in a second configuration according to an exemplary aspect of this disclosure. Figure 9The pitch axis P, fan blades 40, trunnion 44 (having a body 90, a disc 92' with a slot 93, and a coupling device 94), counterweight assembly 80 (having a linkage arm 82, a connection point 96, a lever arm 84 (including a first lever portion 98 and a second lever portion 100), a hinge 86, and a counterweight 88), the path 114 of the lever arm 84, the disc rotation direction 118 of the disc 92', connection point 124, connection point 126, and force F are shown. C .

[0082] This article is in Figure 9 In the middle, hinge 86 connects to lever arm 84 at connection point 124, which is located along a portion of the length of lever arm 84. In contrast, in... Figure 8 In the middle, hinge 86 is connected to lever arm 84 at connection point 126 located at the distal end of lever arm 84. For example... Figure 9 As shown, hinge 86 is connected to lever arm at a distance from connection point 126, wherein connection point 126 is located at the terminal end or distal end of lever arm 84 (particularly the first lever portion 98).

[0083] Figure 9 The illustrated embodiment provides a second configuration for the counterweight assembly 80 and the trunnion 44. This alternative configuration allows for flexibility in kinematic design and allows for variations in part dimensions to accommodate any design or operational requirements.

[0084] Now for reference Figure 10 , Figure 10 This is a simplified perspective view of the fan blade 40, trunnion 44, and counterweight assembly 80, shown in a third configuration according to an exemplary aspect of this disclosure. Figure 10 The diagram shows the pitch axis P, fan blades 40, trunnion 44 (with a body 90, a disc 92' with a slot 93, and a coupling device 94), counterweight assembly 80 (with a linkage arm 82, connection point 96, lever arm 84 (including a first lever portion 98 and a second lever portion 100), hinge 86, counterweight 88, path 114 of lever arm 84, disc rotation direction 118 of disc 92', connection point 124, connection point 126, truss arm 128, connection point 130, connection point 132, angular position 134, locking mechanism 136, and force F. C .

[0085] Truss arm 128 is a solid rod. Connection point 130 is the connection point between the second lever portion 100 and the truss arm 128. Connection point 132 is the connection point between the first lever portion 98 and the truss arm 128. As in the previous embodiment, connection points 130 and 132 may include ball bearing joints. In this example, truss arm 128 provides additional support to the counterweight assembly 80 by supporting the first lever portion 98 to the second lever portion 100. Angular position 134 is a dashed line and represents a predetermined threshold angular position of the lever arm 84.

[0086] Locking mechanism 136 is a mechanical fastener. In this example, locking mechanism 136 may include a latch or catch type device, such as a latch bolt or slam latch. Locking mechanism 136 is positioned along angular position 134. During operation, locking mechanism 136 acts as a lock to prevent any further angular movement of lever arm 84. In one example, locking mechanism 136 may be mounted to disc 42 (e.g., ...). Figure 2 (As shown). In another example, locking mechanism 136 can be mounted to a portion of hinge 86.

[0087] In one example, when the counterweight 88 swings to a fully feathered position during a failure event (e.g., of the gas turbine engine 10), if the lever arm 84 reaches angular position 134, the locking mechanism 136 will engage with the lever arm 84. Once the lever arm 84 reaches angular position 134 and the locking mechanism 136 engages with the lever arm 84 (or counterweight 88), the locking mechanism 136 prevents the counterweight assembly 80 from moving with the variable pitch fan 38 (e.g., the variable pitch fan 38). Figure 1-2 The speed decreases and returns to the higher resistance position (as shown). In one example, the positions of angular position 134 and locking mechanism 136 will be outside the normal operating range of counterweight assembly 80 and will never be at risk of triggering during the normal, non-faulty operating mode of gas turbine engine 10.

[0088] Here Figure 10 In this configuration, hinge 86 connects to lever arm 84 at connection point 124, which is partially located at the point where the first lever portion 98 and the second lever portion 100 connect to each other. In contrast, in... Figure 9 In the middle, hinge 86 is connected to lever arm 84 at connection point 124, which is far from the end of lever arm 84. For example... Figure 10 As shown, hinge 86 is connected to lever arm at a distance from connection point 126, wherein connection point 126 is located at the terminal end or distal end of lever arm 84 (particularly the first lever portion 98).

[0089] Figure 10 The illustrated embodiment provides a third configuration for the counterweight assembly 80 and the trunnion 44. (Compared to...) Figure 9Similar to the embodiments shown, this alternative construction allows for flexibility in kinematic design and the ability to change part dimensions to suit any design or operational requirements. Figure 10 Additional benefits of the configuration shown include additional safety measures (such as locking mechanism 136) during failure modes, for example, when the oil pressure is faced with a sudden drop or loss.

[0090] Now for reference Figure 11 , Figure 11 This is a simplified perspective view of the trunnion 44 and the counterweight assembly 80, shown in a fourth configuration according to an exemplary aspect of this disclosure. Figure 11 The diagram shows the pitch axis P, fan blades 40, trunnion 44 (having a body 90, a disc 92' with a slot 93, and a coupling device 94), counterweight assembly 80 (having a linkage arm 82, a connection point 96, a lever arm 84 (including a first lever portion 98 and a second lever portion 100), a hinge 86, and a counterweight 88), sleeve 110, path 114 of lever arm 84, disc rotation direction 118 of disc 92', connection point 124, connection point 126, and force F. C .

[0091] Here, Figure 11 The illustrated embodiments are similar to Figure 8 The embodiment shown, but Figure 11 Hinge 86 is shown to be positioned radially outward from connection points 124 and 126. Conversely, Figure 8 Hinge 86 is shown positioned radially inward from connection points 124 and 126. In this example, link arm 82 is connected to engagement device 94 at retaining element 95.

[0092] Figure 11 The illustrated embodiment provides a fourth configuration for the counterweight assembly 80 and the trunnion 44. Similar to... Figure 9 and Figure 10 The embodiments shown, such as Figure 11 The alternative construction shown allows for flexibility in kinematic design and enables part dimensions to be varied to suit any design or operational requirements.

[0093] What will be understood is that, for clarity, from Figure 2-14 Certain aspects of the variable pitch fan 38 are omitted in the exemplary embodiments described herein. For example, the provided exemplary configuration of the variable pitch fan 38 does not include a main pitch changing mechanism, such as a linear or rotary pitch changing mechanism. However, it will be understood that in each of the above configurations, a main pitch changing mechanism may be provided, which is coupled to the trunnion 44, for example, to the body 90 coupled to the trunnion 44, and / or via an arm separate from the disk 92'. As will be understood from the description herein, the counterweight assembly 80 may be used to change the pitch of the variable pitch fan 38 in the event of a failure of the main pitch changing mechanism (not shown).

[0094] Now for reference Figure 12 , Figure 12 This is a simplified side view of the trunnion 44 and counterweight assembly 80 attached to the main pitch changing mechanism according to an exemplary aspect of this disclosure. In the illustrated embodiment, the main pitch changing mechanism is a linear actuator 138. Figure 12 The diagram shows the pitch axis P, fan blades 40, trunnion 44 (having a body 90, a disc 92' with a slot 93, and a coupling device 94), counterweight assembly 80 (having a linkage arm 82, a connection point 96, a lever arm 84 (including a first lever portion 98 and a second lever portion 100), hinge 86, counterweight 88, path 114 of lever arm 84, connection point 124, connection point 126, truss arm 128, connection point 130, connection point 132, linear actuator 138 (having a first part 140, a second part 142, and a translational direction 144), and force F. C .

[0095] Linear actuator 138 is an actuation device configured to generate or facilitate linear motion. In some examples, linear actuator 138 may be referred to as a pitch changing mechanism. First member 140 is the stationary component of linear actuator 138. First member 140 is configured to remain stationary relative to disk 42 (see example...). Figure 1-2 In one example, the linear actuator 138 can be mounted to disk 42 (e.g., Figure 2-3 (As shown). During operation of the linear actuator 138, the first piece is stationary relative to the second piece 142, the trunnion 44, and the counterweight assembly 80. The second piece 142 is a kinematic or movable component of the linear actuator 138. During operation, the second piece 142 moves relative to the first piece 140, the trunnion 44, and the counterweight assembly 80. In this example, the linkage arm 82 is configured to drive the translation of the linear actuator 138. In this example, the linkage arm 82 is configured to drive the linear translation of the linear actuator 138 such that the linkage arm 82 drives the second piece 142 to move or actuate along the translation direction 144. The translation direction 144 is the direction of linear motion of the second piece 142 when the second piece translates relative to the first piece 140. Furthermore, the engagement device 94 of the trunnion 44 can be rotatably connected to the second piece 142 of the linear actuator. For example, the second piece 142 may include a curved path along which the engagement device 94 travels when the second piece 142 is linearly translated relative to the first piece 140.

[0096] In this example, the linear actuator 138 is integrated into the construction of the trunnion 44 and the counterweight assembly 80, as... Figure 10 As shown (minus locking mechanism 136). In other examples, linear actuator 138 can be... Figure 2-14Any of the construction combinations shown are used to link the counterweight assembly 80 to the trunnion 44. Furthermore, although the main pitch changing mechanism is a linear actuator 138 for the illustrated embodiment, other pitch changing mechanisms may be provided in other embodiments.

[0097] The incorporation of the linear actuator 138 can provide the benefit of converting the force from the counterweight assembly 80 into a more predictable or efficient linear motion as the force from the linkage arm 82 is transmitted to the trunnion 44 in the form of torque. Furthermore, as will be understood, coupling the counterweight assembly 80 to the trunnion 44 via the main pitch changing mechanism opens up a variety of additional design options. For example, with such a configuration, the main pitch changing mechanism can effectively act as a coordinating loop, so that the total number of counterweight assemblies 80 does not need to match the total number of trunnions 44 and fan blades (with...). Figure 2 (Compared to the embodiments). With such a construction, the total number of counterweight components 80 can be less than the total number of trunnions 44 and fan blades, which may result in a less complex component with a heavier counterweight. Alternatively, the total number of counterweight components 80 may be more than the total number of trunnions 44 and fan blades, which may result in a component with a smaller counterweight and improved packaging.

[0098] Now for reference Figure 13 and 14 , Figure 13 This is a bottom view of the trunnion 44 in a first angular position according to an exemplary aspect of this disclosure and shows the pitch axis P, counterweight assembly 80, connecting rod arm 82, slot 93, engagement device 94 and stop 146. Figure 14 This is a bottom view of the trunnion 44 in a second angle position according to an exemplary aspect of this disclosure, showing the pitch axis P, counterweight assembly 80, connecting rod arm 82, slot 93, engagement device 94, stop 146, and rotation direction 150 of the trunnion 44. For clarity, Figure 13 and 14 Discuss them one after the other.

[0099] What will be understood is that, for clarity, from Figure 13 and 14 Certain aspects of the trunnion 44 and the counterweight assembly 80 are omitted. For example, the configuration provided by the trunnion 44 and the counterweight assembly 80 does not include a main pitch changing mechanism, such as a linear or rotary actuator or a pitch changing mechanism. However, it will be understood that in Figure 13 and 14 In the configuration shown, a main pitch changing mechanism can be provided, which is connected to the trunnion 44, for example, to the body 90 connected to the trunnion 44, and / or via an arm separate from the disk 92'. As will be understood from the description herein, in the event of a failure of the main pitch changing mechanism (not shown), the counterweight assembly 80 can be used to change the pitch of the variable pitch fan 38 via the trunnion 44.

[0100] The stop 146 is a solid material component. In this example, the stop 146 comprises a cylinder or tube of solid material. In one example, the stop 146 is mounted and secured to a disc 42 (see example...). Figure 2 A portion of the stop 146 extends through the slot 93. In this example, when the engagement device 94 moves through the slot 93, the slot 93 allows the linkage arm 82 to drive the engagement device 94 without causing the trunnion 44 to move.

[0101] The stop 146 is configured to limit or prevent the engagement device 94 from performing the same amount of angular rotation as the trunnion 44. For example, the stop 146 is a stationary element attached to the disc 42 such that the trunnion 44 rotates relative to the stop 146 (e.g., the stop 146 does not rotate with the trunnion 44). Thus, when the trunnion 44 rotates in the direction of rotation 150 in response to, for example, centrifugal torque, the engagement device 94 engages with the trunnion 44 at one end of the slot 93 until the engagement device 94 contacts the stop 146.

[0102] When the engaging device 94 contacts the stop 146, the stop 146 halts further angular movement of the engaging device 94. As the trunnion 44 continues to rotate in response to the centrifugal torque of the fan blades 40, the stop 146 lifts the engaging device 94 (of the counterweight assembly 80) off the trunnion 44. When the engaging device 94 contacts the stop 146, the engaging device 94 disengages from the trunnion 44, allowing the trunnion 44 to rotate freely without any reaction force from the counterweight assembly 80. This allows for the use of a smaller force to rotate the trunnion 44 (e.g., using a main pitch changing mechanism).

[0103] In one example, the relative starting position between the stop 146 and the trunnion 44 can be set before operation. In this way, the operating range of the counterweight assembly 80 can be adjusted and regulated by the stop 146, thereby changing the performance characteristics of the counterweight assembly 80 and the trunnion 44.

[0104] In one example, the counterweight torque of the counterweight assembly 80 can be adjusted to counteract or suppress the centrifugal torque of the trunnion 44 (and fan blade 40). The effective angular range of the counterweight assembly 80 can be set by adjusting the angular position of the stop 146 relative to the initial angular position of the trunnion 44. By using the counterweight assembly 80 and adjusting the trunnion 44 and the counterweight assembly 80, the net torque (e.g., the difference between the centrifugal torque of the trunnion 44 and the counterweight torque of the counterweight assembly 80) can be reduced to mitigate the effects of the fan blade 40 rotating to an undesirable high-resistance (e.g., fine) position.

[0105] Here, the trunnion 44 with slot 93 and the stop 146 allow one or more counterweight components 80 to be activated only during specific portions of the range of motion of the trunnion 44 (and the corresponding fan blade 40). For example, the stop 146 separates the counterweight component 80 from the blade actuation path. In other words, the slot 93 and the stop 146 are configured to allow the counterweight component 80 to apply rotational force to the trunnion 44 only during certain operating modes. The slot 93 allows the trunnion 44 to remain in motion without the counterweight component 80 counteracting the torsion of the trunnion 44.

[0106] A slot 93 located at the connection point between the connecting arm 82 and the trunnion 44 allows torque from the counterweight assembly 80 to be disengaged from the trunnion 44 within a specific range of motion. This function of the trunnion 44 with the slot 93 effectively stops the engagement of the counterweight assembly 80 with the trunnion 44 until the counterweight assembly 80 is needed to counteract the rotation of the trunnion 44 caused by one or more fan blades 40.

[0107] In the example without stop 146, the counterweight assembly 80 is always engaged with trunnion 44 (via link arm 82 and engagement device 94). In such an example, the counterweight assembly 80 continuously counteracts the centrifugal torque of the fan blades 40 via trunnion 44. Figure 13 and 14 In the example shown, the presence and length of the slot 93, along with the stop 146, allow for customization or adjustment of the effective centrifugal torque applied to the trunnion 44.

[0108] Now for reference Figure 15 , Figure 15 This is a bottom view of the trunnion 44 according to an exemplary aspect of the present disclosure, and shows the pitch axis P, the trunnion 44 (having a first slot 93A and a second slot 93B), the first counterweight assembly 80A (having a first link arm 82A and a first engagement device 94A), the second counterweight assembly 80B (having a second link arm 82B and a second engagement device 94B), the first damper 152A and the second damper 154B.

[0109] In this example, the trunnion 44 includes two slots (e.g., a first slot 93A and a second slot 93B).

[0110] Here, two counterweight components (e.g., first counterweight component 80A and second counterweight component 80B) are operatively connected to the trunnion 44 via a first slot 93A and a second slot 93B.

[0111] The first damper 152A and the second damper 154B are spring members or damping components. In one example, the material of either the first damper 152A or the second damper 154B may include an elastomeric material. In this example, there is a single first damper 152A and two second dampers 152B. In other examples, more than one first damper 152A and more or fewer than two second dampers 152B may be incorporated into the trunnion 44. In one example, the first damper 152A defines a first total resistance, the second damper 154B defines a second total resistance, and the second total resistance of the second damper 154B is different from the first total resistance of the first damper 152A.

[0112] The first damper 152A is located at one end of the first slot 93A and is configured to occupy a portion of the first slot 93A. The first damper 152A is disposed in the first slot 93A to slow down or inhibit the movement of the first engaging device 94A as it moves through the first slot 93A. In other words, the first damper 152A is configured to reduce the speed of the first engaging device 94A as it moves through the first slot 93A.

[0113] The second dampers 154B are disposed adjacent to each other at one end of the second slot 93B. In another example, one of the second dampers 154B may be disposed at the first end of the second slot 93B, while the other of the second dampers 154B may be disposed at the opposite end of the second slot 93B. A second damper 152B is disposed in the second slot 93B to slow down or inhibit the movement of the second engaging device 94B as it moves through the second slot 93B. In other words, the second damper 152B is configured to reduce the speed of the second engaging device 94B as it moves through the second slot 93B.

[0114] The first damper 152A and the second damper 154B function by slowly reducing the deceleration rate of the first engagement device 94 and the second engagement device 94B, so as to soften or slow down the transition of the first engagement device 94 and the second engagement device 94B as they approach one end of the first slot 93A and the second slot 93B, respectively.

[0115] Here, the softening or slowing of the transition between the first damper 152A and the second damper 154B and the first engagement device 94 and the second engagement device 94B allows the first counterweight assembly 80A and the second counterweight assembly 80B to engage with the trunnion 44, preventing immediate engagement. This slowing of engagement helps mitigate excessively fast response times or rates of the first counterweight assembly 80A and the second counterweight assembly 80B, thereby preventing potential overuse of their reaction functions.

[0116] Furthermore, placing more or fewer of the first damper 152A and the second damper 152B in either the first slot 93A or the second slot 93B can further help regulate the response rate of the first counterweight assembly 80A and the second counterweight assembly 80B.

[0117] This written description uses examples to disclose this disclosure, including best practices, and also enables any person skilled in the art to practice this disclosure, including making and using any device or system and performing any combination of methods. The patentable scope of this disclosure is defined by the claims, but may include other examples that would occur to a person skilled in the art. Such other examples are intended to fall within the scope of the claims if they include structural elements that are not indistinguishable from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

[0118] The following items provide further details:

[0119] A fan assembly for a gas turbine engine includes a fan disk, a trunnion, fan blades, and a counterweight assembly. The fan disk is configured to rotate about an axial centerline of the gas turbine engine when mounted in the gas turbine engine. The trunnion is mounted to the fan disk and defines a slot extending through a portion of the trunnion. The fan blades define a pitch axis and are rotatably attached to the fan disk about the pitch axis of the fan disk via the trunnion. The counterweight assembly includes a linkage arm extending to the trunnion; and a coupling device mounted to the linkage arm, the coupling device being movable through the slot of the trunnion.

[0120] The fan assembly according to one or more of these clauses includes: a fan disc configured to rotate about the axial centerline of the gas turbine engine when mounted in the gas turbine engine; a trunnion mounted to the fan disc, the trunnion defining a slot extending through a portion of the trunnion; fan blades defining a pitch axis and rotatably attached to the fan disc about its pitch axis via the trunnion; and a counterweight assembly including a link arm extending to the trunnion and a coupling device mounted to the link arm, wherein the coupling device is configured to move through the slot of the trunnion.

[0121] The fan assembly according to one or more of these clauses, wherein the slot includes a first slot, and wherein the trunnion defines a second slot disposed in the trunnion.

[0122] A fan assembly according to one or more of these clauses, wherein the first slot has one or more dampers defining a first total resistance, wherein the second slot has one or more dampers defining a second total resistance, wherein the second total resistance is different from the first total resistance.

[0123] The fan assembly according to one or more of these clauses further includes a stop, wherein the trunnion is configured to rotate relative to the stop, wherein the stop is configured to engage the engagement device.

[0124] The fan assembly according to one or more of these clauses, wherein the stop is configured to prevent the engagement device from moving through a portion of the slot.

[0125] The fan assembly according to one or more of these clauses further includes a damper located in the slot and configured to occupy a portion of the slot, wherein the damper is configured to engage the engagement device when the engagement device moves through a portion of the slot.

[0126] The fan assembly according to one or more of these clauses further includes a plurality of dampers located in the slot.

[0127] The fan assembly according to one or more of these clauses, wherein the damper includes a spring member.

[0128] The fan assembly according to one or more of these clauses, wherein the damper is made of an elastomeric material.

[0129] According to one or more of these clauses, the fan assembly includes: a body; and a disc connected to the body, the disc defining the slot such that the slot is disposed in a portion of the disc and extends through a portion of the disc.

[0130] According to one or more of these clauses, the fan assembly wherein the slot extends at least about 10° about the pitch axis and at most about 180° about the pitch axis.

[0131] The fan assembly according to one or more of these clauses, wherein the counterweight assembly is a first counterweight assembly, and the fan assembly further includes a second counterweight assembly, wherein the second counterweight assembly is configured to provide an increased force on the trunnion in response to an increased centrifugal load applied to the second counterweight assembly during operation of the fan assembly.

[0132] According to one or more of these clauses, the fan assembly includes a pin configured to engage with and slide along the slot.

[0133] According to one or more of these clauses, the fan assembly includes a disc, wherein the disc defines the slot such that the slot is disposed in the disc, wherein the slot extends through the disc.

[0134] A gas turbine engine defines an axial direction and an axial centerline. The gas turbine engine includes a fan assembly having a fan disk, fan blades, and a first counterweight assembly having a connecting rod arm. A trunnion for the gas turbine engine includes a body extending along a pitch axis and a disk coupled to or integral with the body. The body is configured to be coupled to the fan blades of the fan assembly to allow the fan blades to rotate about the pitch axis. The disk defines a slot for engaging with a coupling device extending from the first connecting rod arm to facilitate movement of the trunnion relative to the first connecting rod arm for a first range of motion.

[0135] The trunnion according to one or more of these clauses further includes a damper located in the slot and configured to occupy a portion of the slot, wherein the damper is configured to engage the engagement device when the engagement device moves through a portion of the slot.

[0136] The trunnion according to one or more of these clauses further includes a damper located in the slot and configured to occupy a portion of the slot, wherein the damper is configured to engage the engagement device when the engagement device moves through a portion of the slot.

[0137] According to one or more of these clauses, the trunnion includes a first slot, wherein the trunnion defines a second slot disposed in the trunnion.

[0138] A trunnion according to one or more of these clauses, wherein the first slot has one or more dampers defining a first total resistance, wherein the second slot has one or more dampers defining a second total resistance, wherein the second total resistance is different from the first total resistance.

[0139] According to one or more of these clauses, the trunnion wherein the second slot is configured to engage with the second link arm of the second counterweight assembly.

[0140] The trunnion according to one or more of these clauses further includes a stop, wherein the trunnion is configured to rotate relative to the stop, wherein the stop is configured to engage the engagement device.

Claims

1. A fan assembly for a gas turbine engine, the gas turbine engine defining an axial direction and an axial centerline, characterized in that, The fan assembly includes: A fan disc configured to rotate about the axial centerline of the gas turbine engine when mounted in the gas turbine engine; A trunnion, the trunnion being mounted to the fan disc, the trunnion defining a slot extending through a portion of the trunnion; Fan blades, the fan blades defining a pitch axis and rotatably attached to the fan disk about the pitch axis of the fan blades via the trunnions; and The counterweight assembly includes: Linkage arm, the linkage arm extending to the trunnion; A coupling device, the coupling device being mounted to the connecting arm, wherein the coupling device is configured to move through the slot of the trunnion; and A damper located in the slot and configured to occupy a portion of the slot, wherein the damper is configured to engage the engagement device when the engagement device moves through a portion of the slot.

2. The fan assembly according to claim 1, characterized in that, in, The slot includes a first slot, wherein the trunnion defines a second slot disposed in the trunnion.

3. The fan assembly according to claim 2, characterized in that, in, The damper is located in the first slot and is the first damper among one or more dampers located in the first slot, wherein the one or more dampers located in the first slot define a first total resistance, wherein the second slot has one or more dampers defining a second total resistance, wherein the second total resistance is different from the first total resistance.

4. The fan assembly according to claim 1, characterized in that, It further includes a stop, wherein the trunnion is configured to rotate relative to the stop, wherein the stop is configured to engage the engagement device.

5. The fan assembly according to claim 4, characterized in that, in, The stop is configured to prevent the engagement device from moving through a portion of the slot.

6. The fan assembly according to claim 1, characterized in that, It further includes a plurality of dampers located in the slot.

7. The fan assembly according to claim 1, characterized in that, in, The damper includes a spring component.

8. The fan assembly according to claim 1, characterized in that, in, The damper is made of an elastomer material.

9. The fan assembly according to claim 1, characterized in that, in, The trunnion includes: Main body; and A disk connected to the body, the disk defining the slot such that the slot is disposed in a portion of the disk and extends through the portion of the disk.

10. The fan assembly according to claim 1, characterized in that, in, The slot extends at least 10° around the pitch axis and at most 180° around the pitch axis.

11. The fan assembly according to claim 1, characterized in that, in, The counterweight assembly is a first counterweight assembly, and the fan assembly further includes a second counterweight assembly, wherein the second counterweight assembly is configured to provide an increased force on the trunnion in response to an increased centrifugal load applied to the second counterweight assembly during operation of the fan assembly.

12. The fan assembly according to claim 1, characterized in that, in, The engagement device includes a pin configured to engage with and slide along the slot.

13. The fan assembly according to claim 1, characterized in that, in, The trunnion includes a disc, wherein the disc defines the slot such that the slot is disposed in the disc, wherein the slot extends through the thickness of the disc.

14. A trunnion for a fan assembly of a gas turbine engine, the gas turbine engine defining an axial direction and an axial centerline, the fan assembly including a fan disk and a first counterweight assembly, the fan disk being configured to rotate about the axial centerline of the gas turbine engine when mounted in the gas turbine engine, the first counterweight assembly including a first connecting rod arm, characterized in that, The trunnion includes: The main body extends along the pitch axis; and A disc, the disc being coupled to or integral with the body, wherein the body is configured to be coupled to the fan blades of the fan assembly to allow the fan blades to rotate about the pitch axis, wherein the disc defines a slot for engaging with a coupling device extending from the first linkage arm to facilitate movement of the trunnion relative to the first linkage arm within a first range of motion; A damper located in the slot and configured to occupy a portion of the slot, wherein the damper is configured to engage the engagement device when the engagement device moves through a portion of the slot.

15. The trunnion according to claim 14, characterized in that, in, The slot includes a first slot, wherein the trunnion defines a second slot disposed in the trunnion.

16. The trunnion according to claim 15, characterized in that, in, The damper is located in the first slot and is the first damper among one or more dampers located in the first slot, wherein the one or more dampers located in the first slot define a first total resistance, wherein the second slot has one or more dampers defining a second total resistance, wherein the second total resistance is different from the first total resistance.

17. The trunnion according to claim 15, characterized in that, in, The second slot is configured to engage with the second link arm of the second counterweight assembly.

18. The trunnion according to claim 14, characterized in that, It further includes a stop, wherein the trunnion is configured to rotate relative to the stop, wherein the stop is configured to engage the engagement device.

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