Gearbox assembly for turbine engine

Abstract

A gearbox assembly for a turbine engine. The turbine engine includes an engine static structure. The gearbox assembly includes a gear assembly, an input shaft coupled to the gear assembly, an output shaft drivingly coupled to the input shaft through the gear assembly, and a gearbox assembly disengagement system. The gearbox assembly disengagement system includes a one-way clutch that engages the gearbox assembly to the engine static structure during normal operation of the turbine engine and disengages the gearbox assembly from the engine static structure during a reverse torque state.

Description

Technical Field

[0001] The present disclosure generally relates to gearbox assemblies for turbine engines, particularly turbine engines for aircraft. Background Art

[0002] A turbine engine typically includes a propeller (e.g., fan or propeller) and a turbocharger (turbo-engine) arranged in flow communication with each other. The turbocharger includes a compressor section, a combustion section, and a turbine section. A gearbox assembly can transfer torque and power from the turbocharger to the propeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The foregoing and other features and advantages will be apparent from the following more particular description of various exemplary embodiments, as illustrated in the drawings, in which like reference numerals generally indicate identical, functionally similar, or structurally similar elements.

[0004] Figure 1 is a schematic cross-sectional view of a turbine engine according to the present disclosure, taken along its longitudinal centerline axis.

[0005] Figure 2A is taken along section line 2A-2A and having a gear assembly according to the present disclosure Figure 1 A schematic cross-sectional view of a turbine engine gearbox assembly.

[0006] Figure 2B According to the present disclosure Figure 1 Schematic partial cross-sectional view of the gearbox assembly and turbine engine taken at detail 2B in FIG.

[0007] Figure 2C According to the present disclosure Figure 2B An enlarged schematic cross-sectional view of a gearbox assembly disengagement system for a gearbox assembly, taken at detail 2C in FIG.

[0008] Figure 2D According to the present disclosure Figure 2C An enlarged schematic partial cross-sectional view of the one-way clutch of the gearbox assembly disengagement system in an engaged position, taken along section line 2D-2D in FIG.

[0009] Figure 2E is in a disengaged position according to the present disclosure Figure 2D An enlarged schematic partial cross-sectional view of a one-way clutch.

[0010] Figure 3A is a section taken along a transverse centerline axis of a gearbox assembly according to another embodiment and having a gear assembly Figure 1A schematic cross-sectional view of a turbine engine gearbox assembly.

[0011] Figure 3B is a section of a turbine engine according to the present disclosure taken along the longitudinal centerline axis having Figure 3A A schematic partial cross-sectional view of a gear assembly, a gearbox assembly and a turbine engine.

[0012] Figure 3C According to another embodiment, Figure 3A and Figure 3B An enlarged schematic cross-sectional view of a gearbox assembly disengaging the gearbox assembly from the system.

[0013] Figure 3D According to another embodiment, Figure 3C An enlarged schematic partial cross-sectional view of the one-way clutch of the gearbox assembly disengagement system in an engaged position, taken along section line 3D-3D in FIG.

[0014] Figure 3E is in a disengaged position according to the present disclosure Figure 3D An enlarged schematic partial cross-sectional view of a one-way clutch. DETAILED DESCRIPTION

[0015] Features, advantages, and embodiments of the present disclosure are set forth or apparent by considering the following detailed description, drawings, and claims. Furthermore, the following detailed description is exemplary and is intended to provide further explanation without limiting the scope of the disclosure as claimed.

[0016] Various embodiments of the present disclosure are discussed in detail below. Although specific embodiments are discussed, this is for illustrative purposes only. Those skilled in the relevant art will recognize that other components and configurations may be used without departing from the spirit and scope of the present disclosure.

[0017] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of each component.

[0018] 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 is flowing, and "downstream" refers to the direction toward which the fluid is flowing.

[0019] The terms "fore" and "aft" refer to relative positions within a turbine engine or vehicle and refer to the normal operating attitude of the turbine engine or vehicle. For example, with respect to a high-bypass turbine engine, the front position refers to a position closer to the engine inlet, while the aft position refers to a position closer to the engine nozzle or exhaust. In one example, in a reverse-flow turbine engine, the front position refers to a position closer to the engine nozzle or exhaust, while the aft position refers to a position closer to the engine inlet.

[0020] Unless otherwise indicated herein, the terms "coupled," "fixed," "attached," "connected," and the like refer to both direct coupling, fixing, attachment, or connection as well as indirect coupling, fixing, attachment, or connection through one or more intermediate components or features.

[0021] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0022] As used herein, the terms "axial" and "axially" refer to directions and orientations extending generally parallel to the centerline of a turbine engine. Furthermore, the terms "radial" and "radially" refer to directions and orientations extending generally perpendicular to the centerline of a turbine engine. Furthermore, as used herein, the terms "circumferential" and "circumferentially" refer to directions and orientations extending in an arc about the centerline of a turbine engine.

[0023] As used herein, a "propeller" is a component of a turbine engine that is drivingly coupled to a turbocharger engine so that rotation of the turbocharger engine component causes the propeller to rotate and generate thrust. A propeller may include a fan or a propeller. In a turbofan engine (ducted or non-ducted), the propeller is a fan. In a turboprop engine, the propeller is a propeller.

[0024] As used herein, "normal operation" of a turbine engine refers to when the turbine engine is operating and torque is transferred from the turbocharger engine to the propeller through the gearbox assembly in an operating torque direction.

[0025] As used herein, a "reverse torque condition" refers to when torque is transmitted from the output shaft to the input shaft through the gearbox assembly in a reverse torque direction relative to the operating torque direction. A reverse torque condition may occur when the gearbox assembly or the turbine engine is shut down. In the case of a turbine engine, a reverse torque condition may occur when the propeller windmills and causes the propeller shaft to rotate, thereby rotating the gears of the gearbox assembly.

[0026] As used herein, "windmilling" or "windmilling" is a condition when the propeller and low-pressure shaft of a turbine engine continue to rotate at a low speed, while the high-pressure shaft rotates slowly or even stops. Windmilling may occur when the turbine engine is shut down but air is still flowing through the propeller (e.g., during an in-flight engine shutdown), or when the turbine engine is on the ground and the propeller rotates in the presence of wind while the turbine engine is shut down. During windmilling, torque is transmitted from an output shaft (e.g., a propeller) to an input shaft (e.g., a turbocharger engine) through a gearbox assembly in a windmilling rotational direction opposite to the operating rotational direction (e.g., a reverse torque rotational direction).

[0027] As used herein throughout the specification and claims, approximating language is applied to modify any quantitative expression that can be permitted to vary without resulting in a change in the basic function to which it is related. Thus, values modified by terms such as "about," "approximately," "roughly," and "substantially" are not limited to the precise values specified. In at least some cases, approximating language can correspond to the precision of an instrument used to measure a value, or the precision of a method or machine used to construct or manufacture a component or system. For example, approximating language can refer to within one percent, two percent, four percent, ten percent, fifteen percent, or twenty percent of a single value, a range of values, or an endpoint of a defined range of values.

[0028] The present disclosure provides a gearbox assembly for a vehicle having one or more bearings. During operation, the gearbox assembly transmits torque from an input shaft to an output shaft via a gear assembly. In one embodiment, the gearbox assembly is used in a turbine engine, wherein the input shaft is a low-pressure shaft of a turbocharger of the turbine engine, and the output shaft is a propeller shaft of the turbine engine. In this manner, the turbocharger transmits torque to the propeller shaft via the gearbox assembly, thereby rotating the turbine engine's propeller.

[0029] The bearings allow for rotation of one or more gears of the gearbox assembly about the bearings. In one embodiment, one or more of the bearings are journal bearings. The bearings may include any type of bearing, such as roller bearings, ball bearings, etc. The bearings, and particularly the journal bearings, are hydrodynamic bearings that typically require a steady supply of lubricant during all phases of operation of the gearbox assembly to properly lubricate the bearings and thereby prevent damage due to sliding contact of the hydrodynamic journal bearings or even ordinary gear meshing interfaces. Typically, a lubrication system supplies lubricant to the bearings during operation of the gearbox assembly (e.g., when the turbine engine or vehicle is powered on and operating).

[0030] After the turbine engine is shut down, the input shaft or output shaft of the gearbox assembly may experience a long period of continuous rotation. For example, when the gearbox assembly is shut down, torque may be transferred from the output shaft to the input shaft in a reverse torque state. In one embodiment, this reverse torque state occurs when the propeller of the turbine engine is windmilling. In this case, the bearings may be affected by not receiving enough lubricant to lubricate the bearings. For example, during the reverse torque state (e.g., windmilling), the rotational speed of the shaft may be too low to power the pump that pumps lubricant to the bearings. In some cases, such as during operation of a vehicle (e.g., when the aircraft's turbine engine is in flight), the lubrication system may lose pressure (e.g., due to a failure of a pump or other component of the lubrication system), rendering the lubrication system unable to provide lubricant to the bearings.

[0031] The severity of lubrication interruption increases when the bearing is a journal bearing, as a lack of lubricant at the journal bearing can lead to journal bearing failure and subsequent gearbox failure, which can cause the input shaft (e.g., the low-pressure shaft) to permanently lock. This failure of the journal bearing is known as journal bearing seizure and occurs when contact occurs between a pin and a bore of one of the gears in the gear assembly, causing a significant increase in wear and friction that can lead to bearing failure. If contact occurs between the journal bearing and the pin during high-power operation, the two components can weld together due to the high temperatures generated by the friction.

[0032] Some gearbox assemblies include an auxiliary lubrication system that includes an auxiliary pump that supplies lubricant to the bearings to prevent damage to the bearings due to insufficient lubricant supply during reverse torque conditions. However, such an auxiliary lubrication system requires an increased complexity in driving the auxiliary pump. In addition, the auxiliary pump requires increased complexity to provide lubricant during high speeds, such as during operation of the gearbox assembly (e.g., a turbine engine or carrier) and during low speeds, such as during reverse torque conditions (e.g., during windmill rotation). During the reverse torque condition, the propeller may rotate in a reverse torque rotational direction that is opposite to the operating rotational direction of the gearbox assembly. This significantly increases the complexity of the auxiliary pump because the auxiliary pump needs to operate over a large speed range and provide a flow of lubricant regardless of the rotational direction of the output shaft (e.g., propeller).

[0033] Therefore, the present disclosure provides a gearbox assembly disengagement system that disengages the gearbox assembly from the static structure of the turbine engine during a reverse torque state. This causes the entire gearbox assembly to rotate during the reverse torque state, so that there is no relative rotation of the gears. Therefore, the bearings do not rotate, and the present disclosure eliminates the need for the turbine engine to have an auxiliary lubrication system to supply lubricant during the reverse torque state. In particular, the output shaft (e.g., a propeller shaft) is disengaged from the gear assembly. This configuration helps simplify the lubrication system by eliminating the need for an auxiliary lubrication system during a reverse torque state (e.g., windmilling).

[0034] The gear assembly includes a first gear, a plurality of second gears, and a third gear. The gearbox assembly disengagement system can be used in a planetary arrangement or a star arrangement of the gear assembly. In a planetary arrangement, the output shaft is drivingly coupled to the plurality of second gears (e.g., via a second gear carrier), and the third gear is coupled to an engine static structure such that the third gear is stationary during normal operation of the gearbox assembly. During a reverse torque condition, the gearbox assembly disengagement system disengages the third gear from the engine static structure, causing the third gear to rotate. In a star arrangement, the output shaft is drivingly coupled to the third gear, and the plurality of second gears (e.g., a second gear carrier) is coupled to the engine static structure such that during normal operation the plurality of second gears are stationary about a longitudinal centerline axis of the turbine engine. During a reverse torque condition, the gearbox assembly disengagement system disengages the second gear carrier from the engine static structure, causing the second gear carrier (e.g., and the plurality of second gears) to rotate about the longitudinal centerline axis.

[0035] During a reverse torque condition, the gearbox assembly disengagement system is actuated to disengage the gear assembly from the engine's static structure by applying torque from the output shaft to the gear assembly. In this manner, the gearbox assembly disengagement system locks the gear assembly to the engine's static structure during normal operation and unlocks the gear assembly from the engine's static structure during a reverse torque condition. The gearbox assembly disengagement system includes a locking system comprising a one-way clutch that engages the gear assembly during normal operation and disengages the gear assembly during a reverse torque condition. Specifically, during normal operation, operating torque is transmitted from the input shaft to the output shaft through the gear assembly in a first torque direction, and during the reverse torque condition, reverse torque is transmitted from the output shaft to the input shaft in a second torque direction opposite the first torque direction. Operating torque in the first torque direction causes the one-way clutch to engage the gearbox assembly (e.g., the second gear carrier or the third gear), such that the one-way clutch prevents the gearbox assembly from rotating. Specifically, during normal operation, the one-way clutch locks the gearbox assembly to the engine's static structure. During the reverse torque state, the reverse torque in the second torque direction disengages the one-way clutch from the gearbox assembly, causing the one-way clutch to allow the gearbox assembly to rotate. This allows the first gear, the second plurality of gears, and the third gear to rotate without relative rotation between the first gear, the second plurality of gears, and the third gear.

[0036] Thus, the gearbox assembly disengagement system of the present disclosure disengages the gearbox assembly from the engine static structure to allow rotation of all gears of the gear assembly. With all gears rotating, there is no relative rotation between the gears, and the bearings do not require lubricant. Thus, the gearbox assembly disengagement system prevents bearing seizure during reverse torque conditions without having to supply lubricant to the bearings during reverse torque conditions. Thus, the gearbox assembly disengagement system of the present disclosure eliminates the need for an auxiliary lubrication system and reduces the complexity of the lubrication system compared to a gearbox assembly without the benefit of the present disclosure. Furthermore, the one-way clutch provides the simplicity of the gearbox assembly disengagement system compared to a disengagement system without the benefit of the present disclosure.

[0037] Referring now to the accompanying drawings, Figure 1 is a schematic cross-sectional view of a turbine engine 10 taken along a longitudinal centerline axis 12 of the turbine engine 10 according to an embodiment of the present disclosure. Figure 1 As shown, the turbine engine 10 defines an axial direction A extending parallel to the longitudinal centerline axis 12 , a radial direction R perpendicular to the axial direction A, and a circumferential direction C extending arcuately about the longitudinal centerline axis 12 .

[0038] Generally, the turbine engine 10 includes a propeller section 14 and a turbocharger 16 disposed downstream of the propeller section 14. The turbocharger 16 includes a compressor section 21, a combustor 26, and a turbine section 27 in series flow relationship. The turbocharger 16 is substantially enclosed within a casing 18 that is substantially tubular and defines a core inlet 20 that is annular about the longitudinal centerline axis 12. Figure 1 As schematically shown in FIG, compressor section 21 includes a supercharger or low-pressure (LP) compressor 22, followed downstream by a high-pressure (HP) compressor 24. Combustor 26 is downstream of compressor section 21. Turbine section 27 is downstream of combustor 26 and includes a high-pressure (HP) turbine 28, followed downstream by a low-pressure (LP) turbine 30. Turbocharged engine 16 also includes an exhaust nozzle section 32, a high-pressure (HP) shaft 34, and a low-pressure (LP) shaft 36 downstream of turbine section 27. HP shaft 34 drivingly connects HP turbine 28 to HP compressor 24, and HP compressor 24, HP turbine 28, and HP shaft 34 are collectively referred to as the HP spool. HP turbine 28 and HP compressor 24 rotate in unison via HP shaft 34. LP shaft 36 drivingly connects LP turbine 30 to LP compressor 22, and LP compressor 22, LP turbine 30, and LP shaft 36 are collectively referred to as the LP spool. LP turbine 30 and LP compressor 22 rotate in unison via LP shaft 36. The compressor section 21 , the combustor 26 , the turbine section 27 , and the exhaust gas injection nozzle section 32 together define a core air flow path.

[0039] for Figure 1 In the embodiment depicted in FIG, the propeller section 14 includes a propeller 38 (eg, a variable pitch propeller) having a plurality of propeller blades 40 coupled to a disk 42 in a spaced apart manner. Figure 1 In some embodiments, the propeller 38 is a fan driven by the turbocharger engine 16. In some embodiments, the propeller 38 is a propeller driven by the turbocharger engine 16. The propeller blades 40 extend outwardly from the disk 42 generally along a radial direction R. In the case of a variable pitch propeller, a plurality of propeller blades 40 are rotatable about a pitch axis P relative to the disk 42 by means of the propeller blades 40 being operably coupled to an actuating member 44, the actuating member 44 being configured to collectively and uniformly vary the pitch of the propeller blades 40. The propeller blades 40, disk 42, and actuating member 44 together are rotatable about the longitudinal centerline axis 12 via a propeller shaft 45, which is powered by the LP shaft 36 across a power gearbox, also referred to as a gearbox assembly 46 (e.g., where the turbine engine 10 is an indirect drive engine). In this manner, the propeller 38 is drivingly coupled to the turbocharger engine 16 and is powered by the turbocharger engine 16. The gearbox assembly 46 is at Figure 1The gearbox assembly 46 is a speed reduction gearbox assembly for adjusting the rotational speed of the propeller shaft 45 when power is transferred from the LP shaft 36 to the propeller shaft 45 , and thus adjusting the rotational speed of the propeller 38 relative to the LP shaft 36 .

[0040] Still refer to Figure 1 In the exemplary embodiment of the present invention, the disk 42 is covered by a propeller hub 48 that is aerodynamically shaped to facilitate airflow through the plurality of propeller blades 40. In addition, the propeller section 14 includes an annular casing or nacelle 50 that circumferentially surrounds the propeller 38 and at least a portion of the turbocharger engine 16. The nacelle 50 is supported relative to the turbocharger engine 16 by a plurality of outlet guide vanes 52 that are circumferentially spaced about the nacelle 50 and the turbocharger engine 16. Furthermore, a downstream section 54 of the nacelle 50 extends over an outer portion of the turbocharger engine 16 and, together with the outer casing 18, defines a bypass airflow passage 56 therebetween.

[0041] During operation of turbine engine 10, a volume of air 58 enters turbine engine 10 through an inlet 60 of nacelle 50 or propeller section 14. As air 58 passes through propeller blades 40, a first portion of the air (also referred to as bypass air 62) is directed into bypass airflow passage 56. Simultaneously, a second portion of the air (also referred to as core air 64) is directed into an upstream section of the core air flow path through core inlet 20 of LP compressor 22. The ratio between bypass air 62 and core air 64 is generally referred to as the bypass ratio. The pressure of core air 64 is then increased by LP compressor 22, thereby generating compressed air 65. Compressed air 65 is directed through HP compressor 24, where its pressure is further increased. Compressed air 65 is then directed into combustor 26, where it is mixed with fuel and ignited to generate combustion gases 66.

[0042] The combustion gases 66 are directed into the HP turbine 28 and expanded therethrough, where a portion of the thermal or kinetic energy from the combustion gases 66 is extracted via one or more stages of HP turbine stator blades 68 and HP turbine rotor blades 70 coupled to the HP shaft 34. This causes the HP shaft 34 to rotate, thereby supporting the operation of the HP compressor 24 via the HP shaft 34 (a self-sustaining cycle). In this manner, the combustion gases 66 act on the HP turbine 28. The combustion gases 66 are then directed into the LP turbine 30 and expanded therethrough. Here, a second portion of the thermal or kinetic energy is extracted from the combustion gases 66 via one or more stages of LP turbine rotor blades 74 and LP turbine stator blades 72 coupled to the LP shaft 36. This causes the LP shaft 36 to rotate, thereby supporting the operation of the LP compressor 22 (a self-sustaining cycle) and the rotation of the propeller 38 via the gearbox assembly 46 via the LP shaft 36. In this manner, the combustion gases 66 act on the LP turbine 30.

[0043] The combustion gases 66 are then directed through the jet exhaust nozzle section 32 of the turbocharger engine 16 to provide propulsive thrust. Simultaneously, the bypass air 62 is directed through the bypass flow passage 56 before being discharged from the propulsor nozzle exhaust section 76 of the turbine engine 10, also providing propulsive thrust. The HP turbine 28, the LP turbine 30, and the jet exhaust nozzle section 32 at least partially define a hot gas path 78 for directing the combustion gases 66 through the turbocharger engine 16.

[0044] Figure 1 The turbine engine 10 depicted in FIG. 1 is provided as an example only. In other exemplary embodiments, the turbine engine 10 may have any other suitable configuration. For example, in other exemplary embodiments, the propeller 38 may be configured in any other suitable manner (e.g., as a fixed-pitch propeller) and may also be supported using any other suitable propeller frame configuration. Furthermore, in other exemplary embodiments, any other suitable number or configuration of compressors, turbines, shafts, or combinations thereof may be provided. In still other exemplary embodiments, aspects of the present disclosure may be incorporated into any other suitable turbine engine (e.g., a turbofan, propfan, turbojet, turboprop, or turboshaft).

[0045] Figure 2A According to the present disclosure Figure 1 Schematic partial cross-sectional view of the gearbox assembly 46 taken along section line 2A-2A. Figure 2B According to the present disclosure Figure 1 Schematic partial cross-sectional view of the gearbox assembly and turbine engine taken at detail 2B in FIG.

[0046] The gearbox assembly 46 includes a gear assembly 100 including a plurality of gears 102, 104, and 106. The plurality of gears 102, 104, and 106 include a first gear 102, a plurality of second gears 104, and a third gear 106. Figure 2A In the embodiment, the first gear 102 is the sun gear, the second gear 104 is the planetary gear, and the third gear is the ring gear. Figure 2A 106, but the gear assembly 100 may include one or more first gears 102, one or more second gears 104, and one or more third gears 106. The plurality of second gears 104 are constrained by a second gear carrier 108. The gearbox assembly 46 also includes an input shaft and an output shaft. Figure 2B As shown, the input shaft is the LP shaft 36 and the output shaft is the propeller shaft 45. In some embodiments, the input shaft is the HP shaft 34. The output shaft is the propeller shaft 45, so that the turbocharged engine 16 ( Figure 1 ) drives the propeller 38 through the gearbox assembly 46 ( Figure 1 ).

[0047] The gear assembly 100 can be arranged as an epicyclic gear assembly. In an epicyclic gear assembly, the gear assembly 100 can be arranged in a planetary arrangement, wherein the third gear 106 is held stationary and the second gear carrier 108 is allowed to rotate. In such an arrangement, the output shaft (e.g., the propeller shaft 45) is driven by the second gear carrier 108. For example, the second gear carrier 108 is coupled to the propeller shaft 45 such that rotation of the second gear carrier 108 causes the propeller shaft 45 to rotate, and therefore causes the propeller 38 to rotate. In this way, the plurality of second gears 104 (e.g., via the second gear carrier 108) are outputs of the gear assembly 100. However, other suitable types of gear assemblies may be employed, such as a star arrangement, as described below with respect to Figure 3A and Figure 3B In this manner, at least one of third gear 106 or second gear carrier 108 is stationary during normal operation of gearbox assembly 46 (e.g., of turbine engine 10) and is prevented from rotating about longitudinal centerline axis 12. Although an epicyclic gear assembly is described in detail herein, gear assembly 100 may include any type of gear assembly, including, for example, a compound gear assembly, a multi-stage gear assembly, etc.

[0048] First gear 102 is coupled to the input shaft of gearbox assembly 46 such that rotation of the input shaft causes rotation of first gear 102. Specifically, first gear 102 is coupled to LP shaft 36 such that rotation of LP shaft 36 causes rotation of first gear 102. In this manner, the input shaft applies input torque 103 in the input torque direction through first gear 102, causing first gear 102 to rotate in a first rotational direction. Radially outwardly of and intermeshing with first gear 102 are a plurality of second gears 104 supported by a second gear carrier 108. Second gear carrier 108 supports and constrains the plurality of second gears 104 such that each of the plurality of second gears 104 is capable of rotating about a second gear longitudinal centerline axis of each of the plurality of second gears 104 and about the periphery of first gear 102 (about the longitudinal centerline axis 12 of turbine engine 10). In particular, the first gear 102 transmits the input torque 103 to the plurality of second gears 104 such that the first gear 102 applies the output torque 105 to the plurality of second gears 104 in the output torque direction, causing the plurality of second gears 104 to rotate about the longitudinal centerline axis 12 in the second rotational direction. Figure 2A and Figure 2B In the embodiment of the present invention, the output torque direction is opposite to the input torque direction, so that the second rotation direction is opposite to the first rotation direction. In this way, the plurality of second gears 104 rotate the second gear carrier 108, which rotates to drive the rotation of the output shaft. In particular, the second gear carrier 108 is coupled to the propeller 38 ( Figure 1 ), and rotates to drive the propeller 38 to rotate about the longitudinal centerline axis 12 in a second rotational direction.

[0049] Radially outwardly of and intermeshing with the plurality of second gears 104 is a third gear 106, which is an annular ring gear. Specifically, the plurality of second gears 104 react against the stationary third gear 106, such that the third gear 106 applies a reaction torque 107 to the plurality of second gears 104 in the direction of the reaction torque. The direction of the reaction torque is opposite to the direction of the output torque. Figure 2A and Figure 2B In the embodiment, the direction of the reaction torque is the same as the direction of the input torque.

[0050] like Figure 2BAs shown, the turbine engine 10 includes an engine static structure 19. The engine static structure 19 is a non-rotating portion of the turbine engine 10 and forms an internal portion of the core air flow path. The gearbox assembly 46 is coupled to the engine static structure 19 via a gearbox assembly coupling 120. The gearbox assembly coupling 120 is coupled to the third gear 106 such that the gearbox assembly coupling 120 transfers the load from the third gear 106 to the engine static structure 19. The gearbox assembly 46 includes a gearbox assembly disconnect system 200 that selectively disconnects the gearbox assembly 46 from the engine static structure 19 such that the gearbox assembly 46 rotates with the propeller 38 ( Figure 1 ), as described in further detail below.

[0051] Figure 2C According to the present disclosure Figure 2B An enlarged schematic cross-sectional view of the gearbox assembly disengagement system 200 taken at detail 2C in FIG. Figure 2C The third gear 106 is shown to include a plurality of third gear teeth 110 ( Figure 2C ). The third gear 106 is a compound gear such that the plurality of third gear teeth 110 includes a forward set of third gear teeth 110 and a rearward set of third gear teeth 110. In some embodiments, the third gear 106 includes a single set of third gear teeth 110.

[0052] The gearbox assembly disengagement system 200 includes a one-way clutch 202. The one-way clutch 202 includes a plurality of sprags 204 ( Figure 2C (Only one is shown in FIG. 1 ). A plurality of wedges 204 are disposed between the third gear 106 and the gearbox assembly coupling 120. In particular, the plurality of wedges 204 are disposed between a first wedge seat 206 and a second wedge seat 208. The first wedge seat 206 is defined by the third gear 106 and is annular. For example, the first wedge seat 206 extends substantially axially from the third gear 106. Figure 2C , a first sprag seat 206 is coupled to the third gear 106. In some embodiments, the first sprag seat 206 forms a single unitary component with the third gear 106. A second sprag seat 208 is defined by the gearbox assembly coupling 120 and is annular. For example, the second sprag seat 208 extends substantially axially from the gearbox assembly coupling 120. The first sprag seat 206 is radially inward of the second sprag seat 208. In some embodiments, the first sprag seat 206 can be radially outward of the second sprag seat 208. The plurality of sprags 204 selectively engage and disengage the third gear 106 (e.g., the first sprag seat 206), as described in further detail below.

[0053] Gearbox assembly disengagement system 200 also includes one or more bearings 210 that support third gear 106 and allow it to rotate relative to gearbox assembly coupling 120. One or more bearings 210 are roller bearings that include a plurality of rolling elements 212. Specifically, one or more bearings 210 are single-row crossed roller bearings. In this configuration, one or more bearings 210 include a single row of rolling elements 212. One or more bearings 210 constrain third gear 106 in both the axial direction A and the radial direction R using only the single row of rolling elements 212. Specifically, the rolling elements 212 are arranged at an angle to distribute load between third gear 106 and gearbox assembly coupling 120 in both the axial direction A and the radial direction R. One or more bearings 210 also constrain bending moments perpendicular to the axis of rotation of third gear 106. Thus, the one or more bearings 210 support the third gear 106 in all degrees of freedom except rotational direction, to allow the third gear 106 to rotate when the one-way clutch 202 is disengaged, as described in further detail below. The one or more bearings 210 include a plurality of rings 214 that constrain a plurality of rolling elements 212 therein. Specifically, the plurality of rings 214 include a first ring 214a and a second ring 214b, and the plurality of rolling elements 212 are disposed between the first ring 214a and the second ring 214b.

[0054] One or more bearings 210 are coupled to the third gear 106 and the gearbox assembly coupling 120 via one or more coupling mechanisms 216. The one or more coupling mechanisms 216 may include, for example, bolts, pins, etc., for securing the one or more bearings 210 to the third gear 106 and the gearbox assembly coupling 120. Specifically, the one or more coupling mechanisms 216 include a first coupling mechanism 216a and a second coupling mechanism 216b. A first ring 214a is coupled to the third gear 106 via the first coupling mechanism 216a. A second ring 214b is coupled to the gearbox assembly coupling 120 via the second coupling mechanism 216b. In some embodiments, the third gear 106 defines the first ring 214a, such that the first ring 214b and the third gear 106 form a single, unitary component. In some embodiments, the gearbox assembly coupling 120 defines the second ring 214b, such that the second ring 214b and the gearbox assembly coupling 120 form a single, unitary component.

[0055] Figure 2D According to the present disclosure Figure 2C An enlarged schematic partial cross-sectional view of the one-way clutch 202 in the engaged position, taken along section line 2D-2D in FIG. Figure 2E is in a disengaged position according to the present disclosure Figure 2D2 is an enlarged schematic partial cross-sectional view of the one-way clutch 202. A plurality of sprags 204 are circumferentially spaced about the third gear 106 (first sprag seat 206) and the gearbox assembly coupling 120 (second sprag seat 208). Each sprag 204 is rotatably coupled about a pin 205. The sprags 204 are directly or indirectly coupled to the gearbox assembly coupling 120 (second sprag seat 208). Figure 2D and Figure 2E In the embodiment of FIG, the sprag 204 is shown coupled to the radially inner surface 209 of the gearbox assembly coupling 120 (the second sprag seat 208). The sprag 204 selectively engages the radially outer surface 207 of the third gear 106 (the first sprag seat 206), as described in further detail below.

[0056] refer to Figure 2B and Figure 2D When the gearbox assembly 46 (turbine engine 10) is operating during normal operation, the input shaft (e.g., LP shaft 36) rotates, which causes torque to be transferred from the input shaft to the output shaft (e.g., propeller shaft 45) through the gearbox assembly 46. This causes the output shaft to rotate in the operating rotational direction. During normal operation, the gearbox assembly disengagement system 200 engages the gearbox assembly 46 (e.g., third gear 106), causing the gearbox assembly 46 to engage with the gearbox assembly coupling 120. This prevents the gearbox assembly 46 (e.g., third gear 106) from rotating. Specifically, a plurality of sprags 204 engage with the gearbox assembly 46 (e.g., first sprag seat 206 of third gear 106) and the gearbox assembly coupling 120 (e.g., second sprag seat 208). That is, friction between the sprag 204 and the radially outer surface 207 of the third gear 106 prevents the gearbox assembly (eg, the third gear 106 ) from rotating while the other gears (eg, the first gear 102 and the plurality of second gears 104 ) rotate about the longitudinal centerline axis 12 .

[0057] The torque from the input shaft is transferred to the gearbox assembly coupling 120 through the gear assembly 100. In particular, the gear assembly 100 transfers torque (referred to as the gearbox assembly operating torque 250) from the gearbox assembly 46 (e.g., from the third gear 106) to the gearbox assembly coupling 120, and the gearbox assembly operating torque 250 acts on the gearbox assembly coupling 120. The gearbox assembly operating torque 250 acts in a first torque direction, such as Figure 2D The gearbox assembly operating torque 250 is shown in FIG. The gearbox assembly coupling 120 applies a reaction torque (also referred to as a gearbox assembly coupling reaction torque 252 ) to the gearbox assembly 46 (eg, to the third gear 106 ).

[0058] During normal operation, torque transfer from the gearbox assembly 46 to the gearbox assembly coupling 120, and reaction torque transfer from the gearbox assembly coupling 120 to the gearbox assembly 46, occurs because the plurality of sprags 204 engage (contact) the gearbox assembly 46 (e.g., at a radially outer surface 207 of the third gear 106) and the gearbox assembly coupling 120 (e.g., at a radially inner surface 209 of the gearbox assembly coupling 120). For example, the sprags 204 have a rotational position relative to the pin 205. Figure 2E The disengaged position tends to be more radially inclined. Thus, the third gear 106 and the gearbox assembly 46 are prevented from rotating during normal operation.

[0059] refer to Figure 2B 、 Figure 2C and Figure 2E During a reverse torque condition (e.g., when propeller 38 is windmilling), torque is transferred from the output shaft (e.g., propeller shaft 45) to the input shaft (e.g., LP shaft 36) through gearbox assembly 46. In this condition, the output shaft rotates in the reverse torque rotational direction. During the reverse torque condition, gearbox assembly disengagement system 200 disengages gearbox assembly 46 (e.g., third gear 106), causing gearbox assembly 46 to decouple from gearbox assembly coupling 120. This allows gearbox assembly 46 (e.g., third gear 106) to rotate, eliminating relative rotation of the plurality of gears 102, 104, and 106 of gear assembly 100. Specifically, a plurality of sprags 204 disengage from gearbox assembly 46 (e.g., first sprag seats 206 of third gear 106), allowing the sprags 204 to rotate relative to gearbox assembly coupling 120.

[0060] The torque from the output shaft is transmitted through the gear assembly 100. In particular, the gear assembly 100 transmits torque (referred to as the gearbox assembly reverse torque 260) to rotate the gearbox assembly 46 (e.g., the third gear 106). The gearbox assembly reverse torque 260 acts in the second torque direction, such as Figure 2E The second torque direction is opposite to the first torque direction, so that the gearbox assembly reverse torque 260 is opposite to the gearbox assembly operating torque ( Figure 2D ). This causes the plurality of sprags 204 to disengage from the gearbox assembly 46 (e.g., from the first sprag seat 206 of the third gear 106). In particular, the sprags 204 pivot about the pins 205 to a position greater than Figure 2DThe engaged position is radially tilted to a lesser position. When the sprag 204 is disengaged from the gearbox assembly 46, there is no torque reaction on the gearbox assembly 46 from the gearbox assembly coupling 120. Therefore, the gearbox assembly 46 (e.g., the third gear 106) rotates relative to the gearbox assembly coupling 120 in the gearbox assembly reverse torque rotational direction 262. Therefore, the gearbox assembly 46 (e.g., the third gear 106) rotates during the reverse torque state such that there is no relative rotation between the plurality of gears 102, 104, and 106. In other words, the gears 102, 104, and 106 are static relative to each other.

[0061] During a reverse torque condition, and as the gearbox assembly 46 rotates, the one or more bearings 210 support the gearbox assembly 46. Specifically, the one or more bearings 210 support rotation of the gearbox assembly 46 (e.g., the third gear 106) in the circumferential direction C while constraining the gearbox assembly 46 in the radial direction R and the axial direction A. Thus, the one or more bearings 210 support rotation of the gearbox assembly 46 relative to the gearbox assembly coupling 120 during a reverse torque condition.

[0062] Figure 3A FIG. 1 is a diagram of a turbine engine 10 ( FIG. 2 ) having a gear assembly 300 and taken along a transverse centerline axis of a gearbox assembly 46 according to another embodiment. Figure 1 ) is a schematic cross-sectional view of a gearbox assembly 46. Figure 3B is a schematic partial cross-sectional view of a gearbox assembly 46 and a turbine engine according to the present disclosure, taken at the longitudinal centerline axis 12 of the turbine engine 10. The gear assembly 300 includes a plurality of gears 302, 304, and 306. The plurality of gears 302, 304, and 306 includes a first gear 302, a plurality of second gears 304, and a third gear 306. The plurality of gears 302, 304, and 306 are substantially similar to Figures 2A to 2E The plurality of gears 102 , 104 and 106 . The plurality of second gears 304 are constrained by the second gear carrier 308 .

[0063] The gear assembly 300 can be arranged as an epicyclic gear assembly. In an epicyclic gear assembly, the gear assembly 300 can be arranged as a star arrangement or a rotating ring gear type gear assembly (e.g., the third gear 306 rotates about the longitudinal centerline axis 12, while the second gear carrier 308 is fixed and stationary). In such an arrangement, the output shaft (e.g., the propeller shaft 45) is driven by the third gear 306. For example, the third gear 306 is coupled to the propeller shaft 45 ( Figure 1), such that rotation of the third gear 306 causes rotation of the propeller shaft 45 and, therefore, of the propeller 38. In this manner, the third gear 306 is the output of the gear assembly 300. Although an epicyclic gear assembly is described in detail herein, the gear assembly 300 can include any type of gear assembly, including, for example, a compound gear assembly, a multi-stage gear assembly, and the like.

[0064] First gear 302 is coupled to the input shaft of gearbox assembly 46 such that rotation of the input shaft causes rotation of first gear 302. Specifically, first gear 302 is coupled to LP shaft 36 such that rotation of LP shaft 36 causes rotation of first gear 302. In this manner, the input shaft applies input torque 303 in the input torque direction through first gear 302, causing first gear 302 to rotate in a first rotational direction. Radially outwardly of and intermeshing with first gear 302 are a plurality of second gears 304 supported by a second gear carrier 308. Second gear carrier 308 supports and constrains the plurality of second gears 304, enabling each of the plurality of second gears 304 to rotate about a second gear longitudinal centerline axis of each of the plurality of second gears 304, while preventing the plurality of second gears 304 from rotating about the periphery of first gear 302 (about the longitudinal centerline axis 12 of turbine engine 10).

[0065] Radially outwardly of and intermeshing with the plurality of second gears 304 is a third gear 306, which is an annular ring gear. Specifically, the plurality of second gears 304 transmit the input torque 303 to the third gear 306, thereby applying the output torque 305 to the third gear 306 and causing the third gear 306 to rotate in the second rotational direction about the longitudinal centerline axis 12. Figure 3A and Figure 3B In the embodiment of the present invention, the direction of the output torque is the same as the direction of the input torque, so that the second rotational direction is the same as the first rotational direction. In this way, the third gear 306 rotates and drives the rotation of the output shaft. In particular, the third gear 306 is coupled to the propeller 38 ( Figure 1 ), and rotates to drive the propeller 38 to rotate about the longitudinal centerline axis 12 in a second rotational direction.

[0066] The plurality of second gears 304 stationary relative to the longitudinal centerline axis 12 apply a reaction torque 307 to the second gear carrier 308 in the reaction torque direction. The reaction torque direction is opposite to the output torque direction. Figure 3A and Figure 3B In the embodiment, the direction of the reaction torque is opposite to the direction of the input torque.

[0067] like Figure 3BAs shown, the gearbox assembly 46 is coupled to the engine static structure 19 via a gearbox assembly coupling 320. The gearbox assembly coupling 320 is coupled to the second gear carrier 308 such that the gearbox assembly coupling 320 transfers loads from the second gear carrier 308 to the engine static structure 19. Figure 3A and Figure 3B In the embodiment of the present invention, the gearbox assembly 46 includes a gearbox assembly disengagement system 400 that selectively disengages the gearbox assembly 46 from the engine static structure 19 so that the gearbox assembly 46 moves with the propeller 38 ( Figure 1 ), as described in further detail below.

[0068] Figure 3C According to the present disclosure Figure 3B An enlarged schematic cross-sectional view of a gearbox assembly disengagement system 400 taken at detail 3C in FIG. The gearbox assembly disengagement system 400 includes a one-way clutch 402. The one-way clutch 402 includes a plurality of sprags 404 (in Figure 3C (Only one is shown in FIG. 1 ). A plurality of wedges 404 are disposed between the second gear carrier 308 and the gearbox assembly coupling 320. In particular, the plurality of wedges 404 are disposed between a first wedge seat 406 and a second wedge seat 408. The first wedge seat 406 is defined by the gearbox assembly coupling 320 and is annular. For example, the first wedge seat 406 extends substantially axially from the gearbox assembly coupling 320. Figure 3C , a first sprag seat 406 is coupled to the gearbox assembly coupling 320. In some embodiments, the first sprag seat 406 forms a single unitary component with the gearbox assembly coupling 320. A second sprag seat 408 is defined by the second gear carrier 308 and is annular. For example, the second sprag seat 408 extends substantially axially from the second gear carrier 308. The first sprag seat 406 is radially inward of the second sprag seat 408. In some embodiments, the first sprag seat 406 can be radially outward of the second sprag seat 408. The plurality of sprags 404 selectively engage and disengage the second gear carrier 308 (e.g., the second sprag seat 408), as described in further detail below.

[0069] Gearbox assembly decoupling system 400 also includes one or more bearings 410 that support second gear carrier 308 and allow second gear carrier 308 to rotate relative to gearbox assembly coupling 320. One or more bearings 410 are roller bearings that include a plurality of rolling elements 412. Specifically, one or more bearings 410 are single-row crossed roller bearings. In this configuration, one or more bearings 410 include a single row of rolling elements 412. One or more bearings 410 constrain second gear carrier 308 in both the axial direction A and the radial direction R using only the single row of rolling elements 412. Specifically, rolling elements 412 are arranged at an angle to distribute load between second gear carrier 308 and gearbox assembly coupling 320 in both the axial direction A and the radial direction R. One or more bearings 410 also constrain bending moments perpendicular to the rotational axis of second gear carrier 308. In this manner, the one or more bearings 410 support the second gear carrier 308 in all degrees of freedom except rotational direction, allowing the second gear carrier 308 to rotate when the one-way clutch 402 is disengaged, as described in further detail below. The one or more bearings 410 include a plurality of rings 414 that constrain a plurality of rolling elements 412 therein. Specifically, the plurality of rings 414 include a first ring 414a and a second ring 414b, and the plurality of rolling elements 412 are disposed between the first ring 414a and the second ring 414b.

[0070] One or more bearings 410 are coupled to the second gear carrier 308 and the gearbox assembly coupling 320 via one or more coupling mechanisms 416. The one or more coupling mechanisms 416 may include, for example, bolts, pins, etc., for securing the one or more bearings 410 to the second gear carrier 308 and the gearbox assembly coupling 320. Specifically, the one or more coupling mechanisms 416 include a first coupling mechanism 416a and a second coupling mechanism 416b. A first ring 414a is coupled to the second gear carrier 308 via the first coupling mechanism 416a. A second ring 414b is coupled to the gearbox assembly coupling 320 via the second coupling mechanism 416b. In some embodiments, the second gear carrier 308 defines the first ring 414a, such that the first ring 414a and the second gear carrier 308 form a single, unitary component. In some embodiments, the gearbox assembly coupling 320 defines the second ring 414b, such that the second ring 414b and the gearbox assembly coupling 320 form a single, unitary component.

[0071] Figure 3D According to the present disclosure Figure 3C An enlarged schematic partial cross-sectional view of the one-way clutch 402 in the engaged position, taken along section line 3D-3D in FIG. Figure 3E is in a disengaged position according to the present disclosure Figure 3DFIG4 is an enlarged schematic partial cross-sectional view of a one-way clutch 402. A plurality of sprags 404 are circumferentially spaced about the gearbox assembly coupling 320 (first sprag seat 406) and the second gear carrier 308 (second sprag seat 408). Each sprag 404 is rotatably coupled about a pin 405. The sprags 404 are directly or indirectly coupled to the gearbox assembly coupling 320 (first sprag seat 406). Figure 3D and Figure 3E In the embodiment of FIG, the sprag 404 is shown coupled to a radially outer surface 407 of the gearbox assembly coupling 320 (a first sprag seat 406). The sprag 404 selectively engages a radially inner surface 409 of the second gear carrier 308 (a second sprag seat 408), as described in further detail below.

[0072] refer to Figure 3B and Figure 3D When the gearbox assembly 46 (turbine engine 10) is operating during normal operation, the input shaft (e.g., LP shaft 36) rotates, which causes torque to be transferred from the input shaft to the output shaft (e.g., propeller shaft 45) through the gearbox assembly 46. This causes the output shaft to rotate in the operating rotational direction. During normal operation, the gearbox assembly disengagement system 400 engages the gearbox assembly 46 (e.g., second gear carrier 308), causing the gearbox assembly 46 to engage with the gearbox assembly coupling 320. This prevents the gearbox assembly 46 (e.g., second gear carrier 308) from rotating. In particular, a plurality of sprags 404 engage with the gearbox assembly 46 (e.g., second sprag seat 408 of second gear carrier 308) and the gearbox assembly coupling 320 (e.g., first sprag seat 406). That is, friction between the sprag 404 and the radially inner surface 409 of the second gear carrier 308 prevents the gearbox assembly 46 (eg, the second gear carrier 308 ) from rotating while the other gears (eg, the first gear 302 and the third gear 306 ) rotate about the longitudinal centerline axis 12 .

[0073] The torque from the input shaft is transmitted to the gearbox assembly coupling 320 through the gear assembly 300. In particular, the gear assembly 300 transmits torque (referred to as the gearbox assembly operating torque 450) from the gearbox assembly 46 (e.g., from the second gear carrier 308) to the gearbox assembly coupling 320, and the gearbox assembly operating torque 450 acts on the gearbox assembly coupling 320. The gearbox assembly operating torque 450 acts in a first torque direction, such as Figure 3D The gearbox assembly coupling 320 exerts a reaction torque (also referred to as a gearbox assembly coupling reaction torque 452 ) on the gearbox assembly 46 (eg, on the second gear carrier 308 ) that opposes the gearbox assembly operating torque 450 .

[0074] During normal operation, torque transfer from the gearbox assembly 46 to the gearbox assembly coupling 320, and reaction torque transfer from the gearbox assembly coupling 320 to the gearbox assembly 46, occurs because the plurality of sprags 404 engage (contact) the gearbox assembly 46 (e.g., at the radially inner surface 409 of the second gear carrier 308) and the gearbox assembly coupling 320 (e.g., at the radially outer surface 407 of the gearbox assembly coupling 320). Figure 3E Thus, the second gear carrier 308 (eg, the plurality of second gears 304 ) and the gearbox assembly 46 are prevented from rotating about the longitudinal centerline axis 12 during normal operation.

[0075] refer to Figure 3B 、 Figure 3C and Figure 3E During a reverse torque condition (e.g., when propeller 38 is windmilling), torque is transferred from the output shaft (e.g., propeller shaft 45) to the input shaft (e.g., LP shaft 36) through gearbox assembly 46. In this condition, the output shaft rotates in the reverse torque rotational direction. During the reverse torque condition, gearbox assembly disengagement system 400 disengages gearbox assembly 46 (e.g., second gear carrier 308), causing gearbox assembly 46 to decouple from gearbox assembly coupling 320. This allows gearbox assembly 46 (e.g., second gear carrier 308) to rotate, eliminating relative rotation of the plurality of gears 302, 304, and 306 of gear assembly 300. Specifically, the plurality of sprags 404 disengage from gearbox assembly 46 (e.g., second sprag seats 408 of second gear carrier 308), allowing the sprags 404 to rotate relative to gearbox assembly coupling 320.

[0076] The torque from the output shaft is transmitted through the gear assembly 300. In particular, the gear assembly 300 transmits torque (referred to as the gearbox assembly reverse torque 460) to rotate the gearbox assembly 46 (e.g., the second gear carrier 308). The gearbox assembly reverse torque 460 acts in the second torque direction, such as Figure 3E The second torque direction is opposite to the first torque direction, so that the gearbox assembly reverse torque 460 is opposite to the gearbox assembly operating torque ( Figure 3D ). This causes the plurality of sprags 404 to disengage from the gearbox assembly 46 (e.g., from the second sprag seats 408 of the second gear carrier 308). In particular, the sprags 404 pivot about the pins 405 to a position greater than Figure 3DThe engaged position is radially tilted to a lesser position. When the sprag 404 is disengaged from the gearbox assembly 46, there is no torque reaction on the gearbox assembly 46 from the gearbox assembly coupling 320. Therefore, the gearbox assembly 46 (e.g., the second gear carrier 308) rotates relative to the gearbox assembly coupling 320 in the gearbox assembly reverse torque rotation direction 462. Therefore, the gearbox assembly 46 (e.g., the second gear carrier 308) rotates during the reverse torque state such that there is no relative rotation between the plurality of gears 302, 304, and 306. That is, the gears 302, 304, and 306 are static relative to each other.

[0077] During a reverse torque condition, and as the gearbox assembly 46 rotates, the one or more bearings 410 support the gearbox assembly 46. Specifically, the one or more bearings 410 support rotation of the gearbox assembly 46 (e.g., the second gear carrier 308) in the circumferential direction C while constraining the gearbox assembly 46 in the radial direction R and the axial direction A. Thus, the one or more bearings 410 support rotation of the gearbox assembly 46 relative to the gearbox assembly coupling 320 during a reverse torque condition.

[0078] Thus, gearbox assembly disengagement systems 200 and 400 disengage gearbox assembly 46 from engine static structure 19, allowing all gears of gear assemblies 100 and 300 to rotate. With all gears rotating, there is no relative rotation between the gears, and the bearings of gear assemblies 100 and 300 do not require lubricant. Thus, gearbox assembly disengagement systems 200 and 400 prevent bearing seizure during reverse torque conditions without having to supply lubricant to the bearings during reverse torque conditions. Thus, gearbox assembly disengagement systems 200 and 400 eliminate the need for an auxiliary lubrication system and reduce the complexity of the lubrication system compared to gearbox assemblies without the benefit of the present disclosure. Furthermore, one-way clutches 202 and 402 provide the simplicity of gearbox assembly disengagement systems 200 and 400 compared to disengagement systems without the benefit of the present disclosure.

[0079] Further aspects of the disclosure are provided by the subject matter of the following clauses.

[0080] A gearbox assembly for a turbine engine having an engine static structure, comprising: a gear assembly; an input shaft coupled to the gear assembly; an output shaft drivingly coupled to the input shaft through the gear assembly; and a gearbox assembly disengagement system including a one-way clutch that engages the gearbox assembly to the engine static structure during normal operation of the turbine engine and disengages the gearbox assembly from the engine static structure during a reverse torque condition.

[0081] According to the gearbox assembly of the preceding clause, the output shaft transmits a gearbox assembly reverse torque to the gear assembly during the reverse torque state, and the gearbox assembly reverse torque causes the gearbox assembly to be disconnected from the engine static structure by a disengagement system.

[0082] A gearbox assembly according to any preceding clause, further comprising a gearbox assembly coupling coupling the gearbox assembly to the engine static structure, the one-way clutch being disposed between the gearbox assembly and the gearbox assembly coupling.

[0083] A gearbox assembly as claimed in any preceding clause, said one-way clutch comprising a plurality of sprags engaging said gearbox assembly and said gearbox assembly coupling during said normal operation.

[0084] A gearbox assembly according to any preceding clause, wherein each of the plurality of sprags comprises a pin, enabling each of the plurality of sprags to pivot about the pin, and wherein each of the plurality of sprags pivots about the pin during the reverse torque state to disengage the gearbox assembly.

[0085] A gearbox assembly as claimed in any preceding clause, comprising a first sprag seat and the gearbox assembly coupling comprising a second sprag seat, with the plurality of sprags being disposed between the first and second sprag seats.

[0086] A gearbox assembly according to any preceding clause, further comprising one or more bearings disposed between the gearbox assembly and the gearbox assembly coupling, the one or more bearings supporting rotation of the gearbox assembly during the reverse torque condition.

[0087] A gearbox assembly as claimed in any preceding clause, wherein the one or more bearings are single row crossed roller bearings.

[0088] A gearbox assembly as described in any preceding clause, wherein the one or more bearings include a first ring, a second ring, and a plurality of rolling elements disposed between the first ring and the second ring.

[0089] A gearbox assembly as claimed in any preceding clause, the first ring being coupled to the gearbox assembly and the second ring being coupled to the gearbox assembly coupling.

[0090] A gearbox assembly as claimed in any preceding clause, the gear assembly comprising a plurality of gears.

[0091] The gearbox assembly of the preceding clause, wherein the plurality of gears comprises a first gear, a plurality of second gears, and a third gear.

[0092] A gearbox assembly as claimed in any preceding clause, wherein the first gear is a sun gear, the second gear is a planet gear, and the third gear is a ring gear.

[0093] A gearbox assembly as claimed in any preceding clause, wherein the second plurality of gears are constrained by a second gear carrier.

[0094] A gearbox assembly as claimed in any preceding clause, said input shaft being coupled to said first gear and said input shaft driving said first gear during said normal operation.

[0095] A gearbox assembly as claimed in any preceding clause, the output shaft being coupled to the second carrier and the second carrier driving the output shaft during said normal operation.

[0096] A gearbox assembly as claimed in any preceding clause, wherein during said normal operation, said first gear transfers input torque to said plurality of second gears such that said first gear exerts output torque on said plurality of second gears in an output torque direction.

[0097] A gearbox assembly as claimed in any preceding clause, wherein during said normal operation said third gear applies a reaction torque to said plurality of second gears in a reaction torque direction.

[0098] A gearbox assembly as claimed in any preceding clause, wherein the engine static component forms an inner portion of a core air flow path of the turbine engine.

[0099] A gearbox assembly as claimed in any preceding clause, the gearbox assembly coupling being coupled to the third gear such that the gearbox assembly coupling transfers load from the third gear to the engine static component during said normal operation.

[0100] A gearbox assembly as claimed in any preceding clause, the first sprag seat being defined by the third gear and the second sprag seat being defined by the gearbox assembly coupling.

[0101] A gearbox assembly as claimed in any preceding clause, wherein the first sprag seat is radially inwardly of the second sprag seat.

[0102] A gearbox assembly as claimed in any preceding clause, wherein the one or more bearings constrain the third gear in both axial and radial directions.

[0103] A gearbox assembly as claimed in any preceding clause, wherein the plurality of rolling elements are arranged at an angle to distribute load between the third gear and the gearbox assembly coupling.

[0104] A gearbox assembly as claimed in any preceding clause, wherein the one or more bearings are coupled to the gearbox assembly and the gearbox assemblies are coupled via one or more coupling mechanisms.

[0105] The gearbox assembly of the preceding clause, the one or more coupling mechanisms comprising a first coupling mechanism coupling the first ring to the third gear.

[0106] A gearbox assembly as claimed in any preceding clause, the one or more coupling mechanisms comprising a second coupling mechanism coupling the second ring to the gearbox assembly coupling.

[0107] A gearbox assembly as claimed in any preceding clause, said plurality of sprags being coupled to said gearbox assembly coupling.

[0108] A gearbox assembly as claimed in any preceding clause, wherein the gearbox assembly reverses torque acting in a second torque direction opposite to the first torque direction.

[0109] A gearbox assembly as claimed in any preceding clause, wherein the one or more bearings support rotation of the gearbox assembly in a circumferential direction during the reverse torque condition while constraining the gearbox assembly in the radial and axial directions.

[0110] A gearbox assembly as claimed in any preceding clause, said gearbox assembly disengaging system engaging said third gear during said normal operation.

[0111] A gearbox assembly as claimed in any preceding clause, said gearbox assembly disengagement system disengaging said third gear during said reverse torque condition.

[0112] A gearbox assembly as claimed in any preceding clause, the output shaft being coupled to the third gear and the third gear driving the output shaft during said normal operation.

[0113] A gearbox assembly as claimed in any preceding clause, wherein the plurality of second gears transfer the input torque from the first gear to the third gear to impart an output torque on the third gear in an output torque direction.

[0114] A gearbox assembly as claimed in any preceding clause, wherein the second plurality of gears applies a reaction torque to the second carrier in a reaction torque direction opposite to the direction of the output torque.

[0115] A gearbox assembly as claimed in any preceding clause, the gearbox assembly coupling being coupled to the second carrier such that the gearbox assembly coupling transfers loads from the second carrier to the engine static structure during said normal operation.

[0116] A gearbox assembly as claimed in any preceding clause, said gearbox assembly coupling defining said first sprag seat and said second carrier defining said second sprag seat.

[0117] A gearbox assembly as claimed in any preceding clause, wherein the first sprag seat is radially outward of the second sprag seat.

[0118] A gearbox assembly as claimed in any preceding clause, wherein the one or more bearings are provided between the second gear carrier and the gearbox assembly coupling.

[0119] A gearbox assembly as claimed in any preceding clause, the first ring being coupled to the second carrier and the second ring being coupled to the gearbox assembly coupling.

[0120] A gearbox assembly as claimed in any preceding clause, the first ring being coupled to the second carrier via the first coupling mechanism.

[0121] A gearbox assembly as claimed in any preceding clause, the second ring being coupled to the gearbox assembly coupling by the second coupling mechanism.

[0122] A gearbox assembly as claimed in any preceding clause, said gearbox assembly disengagement system engaging said second carrier during said normal operation.

[0123] A gearbox assembly as claimed in any preceding clause, said gearbox assembly disengagement system disengaging said second carrier during said reverse torque condition.

[0124] A turbine engine comprising: a turbocharger engine having a low-pressure shaft; a propeller having a propeller shaft; an engine static structure; and a gearbox assembly comprising: a gear assembly through which the propeller shaft is drivingly coupled to the low-pressure shaft; and a gearbox assembly disengagement system including a one-way clutch that engages the gearbox assembly to the engine static structure during normal operation of the turbine engine and disengages the gearbox assembly from the engine static structure during a reverse torque condition.

[0125] According to any preceding clause of the turbine engine, the propeller shaft transmits gearbox assembly reverse torque to the gear assembly during the reverse torque state, and the gearbox assembly reverse torque causes the gearbox assembly to be disconnected from the system to disconnect the gearbox assembly from the engine static structure.

[0126] A turbine engine according to any preceding clause, further comprising a gearbox assembly coupling coupling the gearbox assembly to the engine static structure, the one-way clutch being disposed between the gearbox assembly and the gearbox assembly coupling.

[0127] The turbine engine of any preceding clause, the one-way clutch comprising a plurality of sprags that engage the gearbox assembly and the gearbox assembly coupling during normal operation.

[0128] A turbine engine according to any preceding clause, each of the plurality of wedges including a pin, enabling each of the plurality of wedges to pivot about the pin, and each of the plurality of wedges pivoting about the pin during the reverse torque condition to disengage the gearbox assembly.

[0129] A turbine engine as described in any preceding clause, wherein the gearbox assembly includes a first wedge seat and the gearbox assembly coupling includes a second wedge seat, and wherein the plurality of wedges are disposed between the first and second wedge seats.

[0130] A turbine engine according to any preceding clause, further comprising one or more bearings disposed between the gearbox assembly and the gearbox assembly coupling, the one or more bearings supporting rotation of the gearbox assembly during the reverse torque condition.

[0131] A turbine engine as claimed in any preceding clause, wherein the one or more bearings are single row crossed roller bearings.

[0132] The turbine engine of any preceding clause, the one or more bearings comprising a first ring, a second ring, and a plurality of rolling elements disposed between the first ring and the second ring.

[0133] The turbine engine of any preceding clause, the first ring being coupled to the gearbox assembly and the second ring being coupled to the gearbox assembly coupling.

[0134] A turbine engine as described in any preceding clause, wherein the gear assembly comprises a plurality of gears.

[0135] The turbine engine according to the preceding clause, wherein the plurality of gears includes a first gear, a plurality of second gears, and a third gear.

[0136] The turbine engine of the preceding clause, wherein the first gear is a sun gear, the second gear is a planet gear, and the third gear is a ring gear.

[0137] A turbine engine as described in any preceding clause, wherein the plurality of second gears are constrained by a second gear carrier.

[0138] The turbine engine of any preceding clause, said low pressure shaft being coupled to said first gear and said low pressure shaft driving said first gear during said normal operation.

[0139] A turbine engine as claimed in any preceding clause, wherein the propeller shaft is coupled to the second carrier and the second carrier drives the propeller shaft during the normal operation.

[0140] A turbine engine as recited in any preceding clause, wherein during said normal operation, said first gear transmits input torque to said plurality of second gears such that said first gear exerts output torque on said plurality of second gears in an output torque direction.

[0141] A turbine engine as claimed in any preceding clause, wherein during said normal operation said third gear applies a reaction torque to said plurality of second gears in a reaction torque direction.

[0142] A turbine engine as claimed in any preceding clause, the turbocharged engine comprising a core air flow path and the engine static component forming an inner portion of the core air flow path.

[0143] A turbine engine as claimed in any preceding clause, the gearbox assembly coupling being coupled to the third gear such that the gearbox assembly coupling transfers load from the third gear to the engine static component during said normal operation.

[0144] A turbine engine as described in any preceding clause, wherein the first sprag seat is defined by the third gear and the second sprag seat is defined by the gearbox assembly coupling.

[0145] A turbine engine as claimed in any preceding clause, wherein the first wedge seat is radially inwardly of the second wedge seat.

[0146] A turbine engine as claimed in any preceding clause, wherein said one or more bearings constrain said third gear in an axial direction and in a radial direction.

[0147] A turbine engine as claimed in any preceding clause, wherein said plurality of rolling elements are arranged at an angle to distribute load between said third gear and said gearbox assembly coupling.

[0148] A turbine engine as claimed in any preceding clause, wherein the one or more bearings are coupled to the gearbox assembly, and wherein the gearbox assembly is coupled via one or more coupling mechanisms.

[0149] The turbine engine of any preceding clause, said one or more coupling mechanisms comprising a first coupling mechanism coupling said first ring to said third gear.

[0150] The turbine engine of any preceding clause, said one or more coupling mechanisms comprising a second coupling mechanism coupling said second ring to said gearbox assembly coupling.

[0151] The turbine engine of any preceding clause, said plurality of sprags being coupled to said gearbox assembly coupling.

[0152] A turbine engine as claimed in any preceding clause, wherein the gearbox assembly reverses torque in a second torque direction opposite to the first torque direction.

[0153] A turbine engine according to any preceding clause, wherein said one or more bearings support rotation of said gearbox assembly in a circumferential direction while constraining said gearbox assembly in said radial direction and said axial direction during said reverse torque condition.

[0154] A turbine engine as in any preceding clause, said gearbox assembly disengagement system engaging said third gear during said normal operation.

[0155] A turbine engine as claimed in any preceding clause, wherein the gearbox assembly disengagement system disengages the third gear during the reverse torque condition.

[0156] A turbine engine as claimed in any preceding clause, wherein the output shaft is coupled to the third gear and wherein the third gear drives the output shaft during normal operation.

[0157] A turbine engine as claimed in any preceding clause, wherein said plurality of second gears transfers said input torque from said first gear to said third gear to impart an output torque on said third gear in an output torque direction.

[0158] A turbine engine as claimed in any preceding clause, wherein the plurality of second gears applies a reaction torque to the second carrier in a reaction torque direction opposite to the direction of the output torque.

[0159] A turbine engine as recited in any preceding clause, the gearbox assembly coupling being coupled to the second carrier such that the gearbox assembly coupling transfers loads from the second carrier to the engine static structure during said normal operation.

[0160] A turbine engine as described in any preceding clause, wherein the gearbox assembly coupling defines the first sprag seat and the second carrier defines the second sprag seat.

[0161] A turbine engine as claimed in any preceding clause, wherein the first wedge seat is radially outward of the second wedge seat.

[0162] A turbine engine as claimed in any preceding clause, wherein the one or more bearings are disposed between the second carrier and the gearbox assembly coupling.

[0163] The turbine engine of any preceding clause, the first ring coupled to the second carrier, and the second ring coupled to the gearbox assembly coupling.

[0164] A turbine engine as claimed in any preceding clause, wherein the first ring is coupled to the second carrier via the first coupling mechanism.

[0165] A turbine engine as claimed in any preceding clause, wherein the second ring is coupled to the gearbox assembly coupling by the second coupling mechanism.

[0166] A turbine engine as in any preceding clause, said gearbox assembly disengagement system engaging said second carrier during said normal operation.

[0167] A turbine engine as in any preceding clause, said gearbox assembly disengagement system disengaging said second carrier during said reverse torque condition.

[0168] A method of engaging and disengaging a gearbox assembly with an engine static structure of a turbine engine, the method comprising: engaging the gearbox assembly to the engine static structure using a one-way clutch during normal operation of the turbine engine; and disengaging the gearbox assembly from the engine static structure using the one-way clutch during a reverse torque condition.

[0169] A method as claimed in any preceding clause, wherein the gearbox assembly is a gearbox assembly as claimed in any preceding clause.

[0170] The method of any preceding clause, further comprising transmitting a gearbox assembly reverse torque to the gear assembly via the output shaft during the reverse torque state, and decoupling the gearbox assembly from the engine static structure via the gearbox assembly reverse torque.

[0171] A method as in any preceding clause, the one-way clutch comprising a plurality of sprags, and the method further comprising engaging the gearbox assembly and the gearbox assembly coupling with the plurality of sprags during the normal operation.

[0172] The method of any preceding clause, each of the plurality of sprags comprising a pin, and further comprising pivoting each of the plurality of sprags about the pin to disengage the gearbox assembly during the reverse torque condition.

[0173] The method of any preceding clause, further comprising supporting rotation of the gearbox assembly during the reverse torque condition, wherein one or more bearings are provided between the gearbox assembly and the gearbox assembly coupling.

[0174] A method as claimed in any preceding clause, the input shaft being coupled to the first gear and further comprising driving the first gear with the input shaft during the normal operation.

[0175] A method as claimed in any preceding clause, the output shaft being coupled to the second carrier, and further comprising driving the output shaft with the second carrier during the normal operation.

[0176] A method as defined in any preceding clause, further comprising transferring input torque from the first gear to the plurality of second gears such that the first gear exerts output torque on the plurality of second gears in an output torque direction during the normal operation.

[0177] A method as in any preceding clause, further comprising applying a reaction torque from said third gear to said plurality of second gears in a reaction torque direction during said normal operation.

[0178] A method as claimed in any preceding clause, the gearbox assembly coupling being coupled to the third gear and further comprising transferring load from the third gear to the engine static component through the gearbox assembly coupling during the normal operation.

[0179] A method as in any preceding clause, further comprising constraining the third gear in an axial direction and a radial direction using the one or more bearings.

[0180] A method as claimed in any preceding clause, wherein the gearbox assembly reverses torque in a second torque direction opposite to the first torque direction.

[0181] A method as in any preceding clause, further comprising engaging said third gear with said one-way clutch during said normal operation.

[0182] A method as in any preceding clause, further comprising disengaging said third gear with said one-way clutch during said reverse torque state.

[0183] A method as claimed in any preceding clause, the output shaft being coupled to the third gear and further comprising driving the output shaft using the third gear during the normal operation.

[0184] A method as defined in any preceding clause, further comprising transmitting the input torque from the first gear to the third gear through the plurality of second gears to impart an output torque on the third gear in an output torque direction.

[0185] A method as in any preceding clause, further comprising applying a reaction torque to the second carrier using the second plurality of gears in a reaction torque direction opposite to the output torque direction.

[0186] The method of any preceding clause, the gearbox assembly coupling being coupled to the second carrier, and further comprising transferring loads from the second carrier to the engine static structure during the normal operation.

[0187] A method as in any preceding clause, further comprising engaging said second carrier with said one-way clutch during said normal operation.

[0188] A method as in any preceding clause, further comprising disengaging the second carrier with the one-way clutch during the reverse torque condition.

[0189] A method of operating a turbine engine according to any preceding clause, the method comprising: transferring torque from the low-pressure shaft to the propeller shaft through the gear assembly during normal operation of the turbine engine; engaging the gearbox assembly to the engine static structure using a one-way clutch during the normal operation; transferring torque from the propeller shaft to the gear assembly during a reverse torque state; and disengaging the gearbox assembly from the engine static structure using the one-way clutch during the reverse torque state.

[0190] A method according to the preceding clause, further comprising a method of engaging and disengaging the gearbox assembly with the engine static structure according to any preceding clause.

[0191] A method as claimed in any preceding clause, the turbine engine being a turbine engine as claimed in any preceding clause.

[0192] Although the above description is directed to preferred embodiments of the present disclosure, other changes and modifications will be apparent to those skilled in the art and may be made without departing from the present disclosure. In addition, features described in conjunction with one embodiment of the present disclosure may be used in conjunction with other embodiments, even if not explicitly stated above.

Claims

1. A gearbox assembly for a turbine engine having an engine static structure, characterized in that: The gearbox assembly comprises: Gear assembly; an input shaft coupled to the gear assembly; an output shaft drivingly coupled to the input shaft through the gear assembly; and A gearbox assembly disengagement system includes a one-way clutch that engages the gearbox assembly to the engine static structure during normal operation of the turbine engine and disengages the gearbox assembly from the engine static structure during a reverse torque condition.

2. The gearbox assembly according to claim 1, characterized in that in, The output shaft transmits a gearbox assembly reverse torque to the gear assembly during the reverse torque state, and the gearbox assembly reverse torque causes the gearbox assembly disengagement system to decouple the gearbox assembly from the engine static structure.

3. The gearbox assembly according to claim 1, wherein: Further included is a gearbox assembly coupling coupling the gearbox assembly to the engine static structure, the one-way clutch being disposed between the gearbox assembly and the gearbox assembly coupling.

4. The gearbox assembly according to claim 3, characterized in that: in, The one-way clutch includes a plurality of sprags that engage the gearbox assembly and the gearbox assembly coupling during the normal operation.

5. The gearbox assembly according to claim 4, characterized in that: in, Each of the plurality of sprags includes a pin such that each of the plurality of sprags can pivot about the pin, and each of the plurality of sprags pivots about the pin during the reverse torque condition to disengage the gearbox assembly.

6. The gearbox assembly according to claim 4, wherein: in, The gearbox assembly includes a first sprag seat, and the gearbox assembly coupling includes a second sprag seat, with the plurality of sprags disposed between the first sprag seat and the second sprag seat.

7. The gearbox assembly according to claim 3, wherein: Further included are one or more bearings disposed between the gearbox assembly and the gearbox assembly coupling, wherein the one or more bearings support rotation of the gearbox assembly during the reverse torque condition.

8. The gearbox assembly according to claim 7, wherein: in, The one or more bearings are single row crossed roller bearings.

9. The gearbox assembly according to claim 7, wherein: in, The one or more bearings include a first ring, a second ring, and a plurality of rolling elements disposed between the first ring and the second ring.

10. The gearbox assembly according to claim 9, wherein: in, The first ring is coupled to the gearbox assembly, and the second ring is coupled to the gearbox assembly coupling.

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