Lubrication system for a turbine engine

Abstract

A lubrication system for a turbine engine. The turbine engine includes a propeller and one or more rotating components. The lubricating system comprises a storage tank, a main lubricating system, an auxiliary lubricating system and a kinetic energy storage system. The reservoir stores a lubricant therein. The main lubrication system supplies lubricant from the sump to one or more rotating components during normal operation of the turbine engine. The auxiliary lubrication system comprises an auxiliary pump, and the auxiliary pump comprises an auxiliary pump shaft. The kinetic energy storage system includes a flywheel that engages the auxiliary pump shaft to power the auxiliary pump when the propeller is wind-rotated such that the auxiliary pump pumps lubricant from the sump to one or more rotating components.

Description

Technical Field

[0001] The present disclosure relates generally to lubrication systems, for example, lubrication systems for turbine engines. Background Art

[0002] A turbine engine generally includes a propeller (eg, fan) and a core section arranged in flow communication with each other. Some turbine engines include one or more rotating components that rotate. A lubrication system provides lubricant to one or more rotating components of a turbine engine. 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 accompanying 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 a longitudinal centerline axis of the turbine engine.

[0005] Figure 2A According to the present disclosure Figure 1 Detailed schematic cross-sectional view of a portion of a turbine engine taken at Detail 2 in FIG. 1 , wherein the lubrication system has an auxiliary lubrication system in a non-operating state.

[0006] Figure 2B According to the present disclosure Figure 1 Detailed schematic cross-sectional view of a portion of turbine engine 10 taken at Detail 2 in FIG. 1 , with the auxiliary lubrication system in operation.

[0007] Figure 3 is a diagram for use in a power gearbox assembly according to the present disclosure taken along the transverse centerline axis Figure 1 A schematic cross-sectional view of a turbine engine power gearbox assembly. DETAILED DESCRIPTION

[0008] Features, advantages and embodiments of the present disclosure are set forth or apparent through consideration of the following detailed description, drawings and claims.In addition, the following detailed description is exemplary and is intended to provide further explanation without limiting the scope of the present disclosure as claimed.

[0009] 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.

[0010] As used herein, the terms “first,” “second,” “third,” and “fourth” may be used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of the respective components.

[0011] The terms "upstream" and "downstream" refer to relative directions relative to the flow of a fluid 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.

[0012] The terms "front" and "rear" 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 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.

[0013] 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.

[0014] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0015] As used herein, the terms "axial" and "axially" refer to directions and orientations extending substantially parallel to the centerline of the turbine engine. Additionally, the terms "radial" and "radially" refer to directions and orientations extending substantially perpendicular to the centerline of the turbine engine. Additionally, as used herein, the terms "circumferential" and "circumferentially" refer to directions and orientations extending in an arc around the centerline of the turbine engine.

[0016] As used herein, a "propeller" is a component of a turbine engine that is drivingly coupled to a core turbine engine such that rotation of the component of the core turbine engine causes the propeller to rotate and generate thrust. The propeller may include a fan or a propeller. In a turbofan engine or an open fan engine, the propeller is a fan. In a turboprop engine, the propeller is a propeller.

[0017] As used herein, "normal operation" of a turbine engine is intended to mean when the turbine engine is operating and the primary lubrication system of the turbine engine is supplying lubricant to one or more rotating components of the turbine engine. Normal operation may include a mission cycle of the turbine engine after the turbine engine is powered on, including, for example, an idle condition, a taxi condition, a takeoff condition, a cruise condition, a descent condition, or a landing condition.

[0018] As used herein, "wind turn" or "wind rotation" 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. Wind rotation may occur when the turbine engine is shut down, but air still flows through the propeller, such as during an engine shutdown in flight, or when the turbine engine is on the ground and the propeller rotates in windy conditions when the turbine engine is shut down. During shutdown, for example, when the aircraft is on the ground, the propeller may also rotate in either direction depending on the fixed position of the turbine engine relative to the ambient wind. Airflow entering the propeller exhaust may exit the propeller inlet in a direction opposite to the operating direction and cause the propeller to rotate in a rotational direction opposite to the intended operating rotational direction.

[0019] As used herein, "operating," "starting," or "activating" an auxiliary lubrication system includes causing lubricant to flow within the auxiliary lubrication system. For example, starting the auxiliary lubrication system includes powering an auxiliary pump to pump lubricant through the auxiliary lubrication system.

[0020] As used herein, "deactivating" an auxiliary lubrication system or an "inoperative" auxiliary lubrication system includes preventing lubricant from flowing within the auxiliary lubrication system. For example, when the auxiliary lubrication system is inoperative, the auxiliary pump is de-energized and is prevented from pumping lubricant through the auxiliary lubrication system.

[0021] Approximate language as used herein throughout the specification and claims is applied to modify any quantitative representation that can allow variation without causing a change in the basic function associated therewith. Therefore, values ​​modified by terms such as "approximately", "approximately", "substantially" and "substantially" are not limited to the specified precise values. In at least some cases, approximate language can correspond to the accuracy of an instrument used to measure a value, or the accuracy of a method or machine used to construct a component or system or to manufacture a component or system. For example, approximate language can refer to within a margin of one, two, four, ten, fifteen or twenty percent in a single value, a range of values ​​or an endpoint of a range of defined values.

[0022] The present disclosure provides a turbine engine with a lubrication system. The turbine engine includes a propeller having a propeller shaft. The turbine engine includes one or more rotating parts rotating in the turbine engine. The one or more rotating parts may include, for example, one or more shafts, one or more gears, or one or more bearings, and the one or more bearings include one or more engine bearings for one or more shafts (e.g., a low-pressure shaft or a high-pressure shaft) of the turbine engine, or one or more power gearbox bearings for a power gearbox assembly of the turbine engine. One or more power gearbox bearings allow one or more power gearbox gears of the power gearbox assembly to rotate around one or more power gearbox bearings. In one embodiment, one or more bearings are journal bearings. One or more bearings may include any type of bearing, for example, such as roller bearings, etc. The lubrication system supplies lubricant (e.g., oil) to one or more rotating parts. The lubrication system includes a storage tank in which the lubricant is stored, and a main lubrication system having a main pump and a main lubricant supply line. During normal operation of the turbine engine, the main pump pumps the lubricant from the storage tank to the one or more rotating parts through the main lubricant supply line.

[0023] Bearings, especially journal bearings, are fluid dynamic bearings that typically require a steady supply of lubricant to properly lubricate the bearings during all phases of operation of the turbine engine to prevent damage caused by sliding contact of the fluid dynamic journal bearings or even the universal gear meshing interface. After the turbine engine is shut down, the shaft of the turbine engine may experience long-term continuous rotation, such as what happens during wind power rotation. In this case, one or more rotating parts, and in particular one or more bearings, may be affected by not receiving enough lubricant to lubricate one or more rotating parts. For example, during wind power rotation, the rotation speed of the shaft may be too low to drive the main pump to pump lubricant to one or more rotating parts. In some cases, for example, during the operation of the turbine engine (e.g., in flight), the lubrication system may lose pressure (e.g., due to a failure of the main pump or other components of the main lubrication system), so that the main lubrication system cannot provide lubricant to one or more rotating parts via the main pump and the main lubricant supply line.

[0024] The severity of lubrication interruption increases when the bearing is a journal bearing, as lack of lubricant at the journal bearing can lead to journal bearing failure and subsequent gearbox failure, which can cause the low-speed shaft to permanently lock up. This failure of the journal bearing is called journal bearing seizure and occurs when there is contact between the planetary gear pin and the gear bore, resulting in a significant increase in wear and friction leading to bearing failure. If contact occurs between the journal bearing and the pin during high power operation, the two components may weld together due to the high temperatures generated by the friction.

[0025] Some turbine engines include an auxiliary lubrication system that includes an auxiliary pump to supply lubricant to one or more rotating parts to prevent damage to the rotating parts due to insufficient lubricant supply during wind rotation. Such an auxiliary pump can be drivingly coupled to a propeller shaft and requires increased complexity for driving the auxiliary pump through the propeller shaft. Further, the auxiliary pump requires increased complexity to provide lubricant during high speeds (such as during operation of the turbine engine) and during low speeds (such as during wind rotation (e.g., in flight or on the ground)). Further, the auxiliary pump requires increased complexity to provide lubricant when the propeller is wind-rotated in either direction (e.g., the propeller rotates clockwise or counterclockwise).

[0026] Therefore, the present disclosure provides an auxiliary lubrication system that supplies lubricant to one or more rotating parts during any time when the main lubrication system cannot supply lubricant. In particular, the present disclosure provides lubricant to one or more rotating parts (e.g., journal bearings) when the turbine engine is shut down or whenever the turbine engine is rotated by wind to avoid the journal bearings from seizing. The present disclosure provides a kinetic energy storage system that stores kinetic energy during normal operation of the turbine engine. In particular, the kinetic energy storage system is drivingly coupled to an accessory gearbox of the turbine engine and is started when the turbine engine is shut down or otherwise rotated by wind. When the turbine engine is shut down, the kinetic energy storage system powers the auxiliary pump by supplying the stored kinetic energy to the auxiliary pump. The kinetic energy storage system includes a flywheel that is mechanically driven via a speed increasing gear of the accessory gearbox. The flywheel rotates and stores kinetic energy through the angular momentum of the flywheel. The kinetic energy storage system includes an electromagnetic clutch that engages the flywheel during normal operation of the turbine engine to prevent the flywheel from engaging the auxiliary pump. During normal operation, and when the clutch is engaged, the flywheel is driven by the accessory gearbox and stores kinetic energy generated by the turbine engine (eg, by rotation of a shaft of the turbine engine).

[0027] The clutch disengages the flywheel upon a run command (e.g., from a controller) or lack of power, and the flywheel is moved by one or more flywheel springs to engage the auxiliary pump shaft to drive the auxiliary pump. The flywheel continues to rotate even though it is no longer engaged with the accessory gearbox due to the angular momentum of the flywheel (e.g., stored kinetic energy). As the flywheel continues to rotate, the flywheel releases kinetic energy and provides power to the auxiliary pump. In this way, the auxiliary pump pumps lubricant to one or more rotating parts (e.g., bearings). The auxiliary pump can be a variable displacement pump so that when the flywheel rotation slows down, the auxiliary pump increases the displacement of the lubricant so that even when the flywheel rotation slows down, the auxiliary pump pumps lubricant at a constant mass flow rate.

[0028] Thus, the auxiliary lubrication system supplies lubricant to one or more rotating components when the turbine engine is shut down or otherwise rotating due to wind. The kinetic energy storage system ensures that the auxiliary pump operates to pump lubricant to the one or more rotating components independently of the direction of rotation of the propeller during wind rotation (e.g., whether the propeller is rotating clockwise or counterclockwise). The kinetic energy storage system also reduces the complexity of the auxiliary lubrication system by providing power to the auxiliary pump independently of the rotation of the propeller shaft or other shafts of the turbine engine.

[0029] Now referring 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 for reference) and a radial direction R perpendicular to the axial direction A. Figure 1 In the orientation of FIG. 1 , the portion of the turbine engine 10 above the longitudinal centerline axis 12 is referred to as the top portion 11, and the portion of the turbine engine 10 below the longitudinal centerline axis 12 is referred to as the bottom portion 13. Typically, the turbine engine 10 includes a propeller section 14 and a core turbine engine 16 disposed downstream of the propeller section 14.

[0030] The depicted core turbine engine 16 generally includes a casing 18 that is substantially tubular and defines an annular inlet 20. Figure 1 As shown schematically, the casing 18 encloses in a serial flow relationship: a compressor section 21, which includes a supercharger or low pressure (LP) compressor 22, followed downstream by a high pressure (HP) compressor 24; a combustion section 26; a turbine section 27, which includes a high pressure (HP) turbine 28, followed downstream by a low pressure (LP) turbine 30; and an ejection exhaust nozzle section 32. A high pressure (HP) shaft 34 or spool drives the HP turbine 28 to the HP compressor 24 so that the HP turbine 28 and the HP compressor 24 rotate in unison. A low pressure (LP) shaft 36 drives the LP turbine 30 to the LP compressor 22 so that the LP turbine 30 and the LP compressor 22 rotate in unison. The HP shaft 34, the LP shaft 36, or both the HP shaft 34 and the LP shaft 36 are supported by one or more engine bearings that allow the HP shaft 34 or the LP shaft 36 to rotate, as described in further detail below. The compressor section 21, the combustion section 26, the turbine section 27, and the ejection exhaust nozzle section 32 together define a core air flow path.

[0031] for Figure 1In the embodiment depicted in FIG. 1 , 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 core turbine engine 16. In some embodiments, the propeller 38 is a propeller driven by the core turbine engine 16. The propeller blades 40 extend outwardly from the disk 42 generally in a radial direction R. Each propeller blade 40 is capable of rotating about a pitch axis P relative to the disk 42 by means of the propeller blades 40 being operably connected to an actuation member 44, and the actuation member 44 is configured to collectively and uniformly change the pitch of the propeller blades 40, as further detailed below. The propeller blades 40, disk 42, and actuation members 44 are capable of rotating together about the longitudinal centerline axis 12 via a propeller shaft 45, and the propeller shaft 45 is powered by the LP shaft 36 across a power gearbox (also referred to as a power gearbox assembly 46). The power gearbox assembly 46 is Figure 1 The power gearbox assembly 46 includes a plurality of power gearbox gears for adjusting the rotational speed of the propeller shaft 45, and thus adjusting the rotational speed of the propeller 38 relative to the LP shaft 36. The power gearbox assembly 46 also includes one or more power gearbox bearings for supporting the rotation of one or more power gearbox gears in the plurality of power gearbox gears, as described in further detail below.

[0032] Still reference Figure 1 In an 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 propeller casing or nacelle 50 that circumferentially surrounds the propeller 38 and at least a portion of the core turbine engine 16. The nacelle 50 is supported relative to the core turbine engine 16 by a plurality of outlet guide vanes 52 that are circumferentially spaced about the nacelle 50 and the core turbine engine 16. In addition, a downstream section 54 of the nacelle 50 extends over an outer portion of the core turbine engine 16 to define a bypass airflow passage 56 therebetween.

[0033] During operation of the turbine engine 10, a quantity of air 58 enters the turbine engine 10 through an inlet 60 of the nacelle 50 or the propeller section 14. As the quantity of air 58 passes through the propeller blades 40, a first portion of the air (referred to as bypass air) 62 is directed or directed into the bypass airflow passage 56, and a second portion of the air (referred to as core air) 64 is directed or directed into an upstream section of the core air flow path, or more specifically, into the annular inlet 20 of the LP compressor 22. The ratio between the bypass air 62 and the core air 64 is generally referred to as the bypass ratio. The pressure of the core air 64 is then increased, generating compressed air 65, and the compressed air 65 is directed through the HP compressor 24 and into the combustion section 26, where the compressed air 65 is mixed with fuel and combusted to generate combustion gases 66.

[0034] The combustion gases 66 are directed into and expanded through the HP turbine 28, wherein a portion of the heat or kinetic energy from the combustion gases 66 is extracted via successive stages of HP turbine stator blades 68 coupled to the casing 18 and HP turbine rotor blades 70 coupled to the HP shaft 34, thereby rotating the HP shaft 34, thereby supporting the operation of the HP compressor 24. The combustion gases 66 are then directed into and expanded through the LP turbine 30. Here, a second portion of the heat or kinetic energy is extracted from the combustion gases 66 via successive stages of LP turbine stator blades 72 coupled to the casing 18 and LP turbine rotor blades 74 coupled to the LP shaft 36, thereby rotating the LP shaft 36, thereby supporting the operation of the LP compressor 22 and the rotation of the propeller 38 via the power gearbox assembly 46.

[0035] The combustion gases 66 are then directed through the jet exhaust nozzle section 32 of the core turbine engine 16 to provide propulsive thrust. At the same time, the pressure of the first portion of air 62 is significantly increased, also providing propulsive thrust, as it is directed through the bypass airflow passage 56 before being discharged from the thruster nozzle exhaust section 76 of the turbine engine 10. 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 core turbine engine 16.

[0036] The controller 79 communicates with the turbine engine 10 for controlling various aspects of the turbine engine 10. For example, the controller 79 is in bidirectional communication with the turbine engine 10 for receiving signals from various sensors and control systems of the turbine engine 10, and for controlling components of the turbine engine 10, as described in further detail below. The controller 79 or components thereof may be onboard the turbine engine 10, onboard an aircraft (not shown), or may be remote from each of the turbine engine 10 and the aircraft. The controller 79 may be a full authority digital engine control (FADEC) that controls various aspects of the turbine engine 10.

[0037] The controller 79 may be a stand-alone controller or may be part of an engine controller to operate various systems of the turbine engine 10. In this embodiment, the controller 79 is a computing device having one or more processors and a memory. The one or more processors may be any suitable processing device, including but not limited to a microprocessor, a microcontroller, an integrated circuit, a logic device, a programmable logic controller (PLC), an application specific integrated circuit (ASIC), or a field programmable gate array (FPGA). The memory may include one or more computer-readable media, including but not limited to non-temporary computer-readable media, computer-readable non-volatile media (e.g., flash memory), RAM, ROM, a hard drive, a flash drive, or other memory devices.

[0038] The memory can store information that can be accessed by one or more processors, including computer-readable instructions that can be executed by one or more processors. The instructions can be any set of instructions or sequence of instructions that cause one or more processors and the controller 79 to operate when executed by one or more processors. The controller 79, and more specifically, one or more processors are programmed or configured to perform these operations, such as the operations discussed further below. In some embodiments, the instructions can be executed by one or more processors to cause one or more processors to complete any operations and functions that the controller 79 is configured for, as will be further described below. The instructions can be software written in any suitable programming language or can be implemented in hardware. Additionally or alternatively, the instructions can be executed in logically or virtually independent threads on the processor. The memory can further store data that can be accessed by one or more processors.

[0039] The techniques discussed herein refer to computer-based systems and the actions taken by computer-based systems and information sent to and from computer-based systems. It will be appreciated by those of ordinary skill in the art that the inherent flexibility of computer-based systems allows for a variety of possible configurations, combinations, and divisions of tasks and functions between and within components. For example, the processes discussed herein can be implemented using a single computing device or multiple computing devices working in combination. Databases, memory, instructions, and applications can be implemented on a single system, or can be distributed on multiple systems. Distributed components can operate sequentially or in parallel.

[0040] Figure 1 The turbine engine 10 depicted in the drawings is for 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. In addition, in other exemplary embodiments, any other suitable number or configuration of compressors, turbines, shafts, or combinations thereof may be provided. In other exemplary embodiments, aspects of the present disclosure may be incorporated into any other suitable turbine engine (e.g., such as a turbofan engine, a propfan engine, a turbojet engine, a turboprop engine, or a turboshaft engine).

[0041] Figure 2A According to the present disclosure Figure 1 Detailed schematic cross-sectional view of a portion of turbine engine 10 taken at Detail 2 in FIG. 1 , wherein lubrication system 100 has auxiliary lubrication system 104 in an inoperative state. Figure 2B According to the present disclosure Figure 1 Detailed schematic cross-sectional view of a portion of turbine engine 10 taken at Detail 2 in FIG. 1 , wherein auxiliary lubrication system 104 is in operation. Figure 2A and 2B As shown, the turbine engine 10 includes one or more engine bearings 37 that support the rotation of the LP shaft 36 and the propeller shaft 45. The one or more engine bearings 37 may also support the rotation of the HP shaft 34. The one or more engine bearings 37 may include any number of engine bearings 37 for supporting the rotation of the shafts of the turbine engine 10. The one or more engine bearings 37 are referred to as rotating components of the turbine engine 10 and may include any type of bearing, such as, for example, a journal bearing, a roller bearing, etc.

[0042] The power gearbox assembly 46 includes a power gearbox gear assembly 47 having a plurality of power gearbox gears 49. The plurality of power gearbox gears 49 include a first power gearbox gear 49a, one or more second power gearbox gears 49b fixed by a planet carrier 51, and a third power gearbox gear 49c. Figure 2A and 2B In the embodiment of the present invention, the first power gearbox gear 49a is a sun gear, the one or more second power gearbox gears 49b are planetary gears, and the third power gearbox gear 49c is a ring gear. The power gearbox gear assembly 47 may be an epicyclic gear assembly. When the power gearbox gear assembly 47 is an epicyclic gear assembly, the one or more second power gearbox gears 49b include a plurality of second power gearbox gears 49b (e.g., two or more second power gearbox gears 49b).

[0043] In the epicyclic gear assembly, the power gearbox gear assembly 47 can be in a star arrangement or a rotating ring gear type gear assembly (e.g., the third power gearbox gear 49c is rotating, while the planet carrier 51 is fixed and stationary). In this arrangement, the propeller 38 is driven by the third power gearbox gear 49c. For example, the third power gearbox gear 49c is coupled to the propeller shaft 45 so that the rotation of the third power gearbox gear 49c rotates the propeller shaft 45, and thus rotates the propeller 38. In this way, the third power gearbox gear 49c is the output of the power gearbox gear assembly 47. However, other suitable types of gear assemblies can be used. In a non-limiting embodiment, the power gearbox gear assembly 47 is a planetary arrangement in which the third power gearbox gear 49c remains fixed and the planet carrier 51 is allowed to rotate. In this arrangement, the propeller 38 is driven by the planet carrier 51. For example, the planet carrier 51 is coupled to the propeller shaft 45 so that the rotation of the planet carrier 51 rotates the propeller shaft 45, and thus rotates the propeller 38. In this manner, one or more second power gearbox gears 49b (e.g., via the planet carrier 51) are outputs of the power gearbox gear assembly 47. In another non-limiting embodiment, the power gearbox gear assembly 47 may be a differential gear assembly in which both the third power gearbox gear 49c and the planet carrier 51 are allowed to rotate. Although an epicyclic gear assembly is described in detail herein, the power gearbox gear assembly 47 may include any type of gear assembly, including, for example, a compound gear assembly, a multi-stage gear assembly, etc.

[0044] The plurality of power gearbox gears 49 include one or more power gearbox bearings 53 disposed therein. For example, the one or more second power gearbox gears 49b each include one or more power gearbox bearings 53 disposed therein. The one or more power gearbox bearings 53 enable the plurality of power gearbox gears 49 to rotate about the one or more power gearbox bearings 53, so that the plurality of power gearbox gears 49 rotate. The one or more power gearbox bearings 53 may include any type of bearing for a gear, such as, for example, a journal bearing, a roller bearing, etc. The plurality of power gearbox gears 49 and the one or more power gearbox bearings 53 are rotating components of the turbine engine 10. Therefore, the turbine engine 10 includes one or more rotating components 55, the one or more rotating components 55 including at least one of the one or more engine bearings 37, the plurality of power gearbox gears 49, or the one or more power gearbox bearings 53. The one or more rotating components 55 may also include the HP shaft 34 or the LP shaft 36.

[0045] The first power gearbox gear 49a is coupled to the input shaft of the turbine engine 10. For example, the first power gearbox gear 49a is coupled to the LP shaft 36 so that the rotation of the LP shaft 36 rotates the first power gearbox gear 49a. Radially outwardly of the first power gearbox gear 49a and intermeshing therewith are one or more second power gearbox gears 49b, which are coupled together and supported by the planet carrier 51. The planet carrier 51 supports and limits the one or more second power gearbox gears 49b so that each of the one or more second power gearbox gears 49b can rotate around the corresponding axis of each second power gearbox gear 49b without rotating around the periphery of the first power gearbox gear 49a. Radially outwardly of the one or more second power gearbox gears 49b and intermeshing therewith is the third power gearbox gear 49c, which is an annular ring gear. The third power gearbox gear 49c is coupled to the propeller 38 via the output shaft and rotates to drive the propeller 38 to rotate around the longitudinal centerline axis 12. For example, the propeller shaft 45 is coupled to the third power gearbox gear 49c.

[0046] Turbine engine 10 includes an accessory gearbox assembly 80. One or more accessories for turbine engine 10 or the aircraft may be coupled to accessory gearbox assembly 80 for providing power to the one or more accessories. Figure 2A and 2BAs shown, the accessory gearbox assembly 80 includes an accessory gearbox housing 82 and an accessory gearbox gear assembly 83 including a plurality of accessory gearbox gears 84. The accessory gearbox gear assembly 83 is disposed in the accessory gearbox housing 82. The plurality of accessory gearbox gears 84 include a first accessory gearbox gear 84a, a second accessory gearbox gear 84b, a third accessory gearbox gear 84c, and a fourth accessory gearbox gear 84d. The plurality of accessory gearbox gears 84 may include any number of gears as desired, and may include any type of gears, such as, for example, spur gears, bevel gears, compound gears, and the like.

[0047] The accessory gearbox assembly 80 includes an accessory gearbox input shaft 86 and one or more output shafts 88. The accessory gearbox input shaft 86 is coupled to one of the plurality of accessory gearbox gears 84 to rotate the plurality of accessory gearbox gears 84, as described in further detail below. Figure 2A and 2B , the accessory gearbox input shaft 86 is coupled to the first accessory gearbox gear 84a. In this manner, rotation of the accessory gearbox input shaft 86 causes the first accessory gearbox gear 84a to rotate. The second accessory gearbox gear 84b is intermeshed with the first accessory gearbox gear 84a. The fourth accessory gearbox gear 84d is intermeshed with the second accessory gearbox gear 84b. The third accessory gearbox gear 84c is intermeshed with the fourth accessory gearbox gear 84d. In some embodiments, the fourth accessory gearbox gear 84d is omitted, and the third accessory gearbox gear 84c is intermeshed with the second accessory gearbox gear 84b.

[0048] The one or more output shafts 88 are coupled to at least one of the plurality of accessory gearbox gears 84 such that rotation of the plurality of accessory gearbox gears 84 causes the one or more output shafts 88 to rotate. Figure 2A and 2B , the one or more output shafts 88 include a first output shaft 88a and a second output shaft 88b. The first output shaft 88a is coupled to the second accessory gearbox gear 84b, and the second output shaft 88b is coupled to the third accessory gearbox gear 84c. The one or more rotating components 55 may include one or more accessory gearbox gears 84, one or more accessory gearbox bearings of the accessory gearbox, or an accessory gearbox input shaft 86, or one or more accessory gearbox output shafts 88.

[0049] The gear ratio of the accessory gearbox gear assembly 83 is greater than 3:1, so that the accessory gearbox gear assembly 83 increases the rotational speed of the one or more output shafts 88 from the accessory gearbox input shaft 86 by at least three times. For example, the second accessory gearbox gear 84b and the third accessory gearbox gear 84c are smaller than the first accessory gearbox gear 84a, so that the second accessory gearbox gear 84b and the third accessory gearbox gear 84c rotate at a greater rotational speed than the first accessory gearbox gear 84a. In this way, the one or more output shafts 88 rotate at a greater rotational speed than the accessory gearbox input shaft 86. Preferably, the gear ratio is in the range of 3:1 to 5:1.

[0050] The accessory gearbox assembly 80 is coupled to the HP shaft 34 via a tower shaft 90 that extends from and is rotatable with the HP shaft 34. In some embodiments, the accessory gearbox assembly 80 is coupled to the LP shaft 36. Figure 2A and 2B , the tower shaft 90 generally extends at least partially in a radial direction R from the HP shaft 34. The tower shaft 90 may extend at an acute angle relative to the longitudinal centerline axis 12, such as Figure 2A and 2B . In some embodiments, the tower shaft 90 can extend substantially perpendicular to the HP shaft 34. The tower shaft 90 can be coupled to the HP shaft 34 by a plurality of gears. The tower shaft 90 is coupled to the accessory gearbox input shaft 86 by a tower shaft gear assembly 92 having a plurality of tower shaft gears 94. The plurality of tower shaft gears 94 can be bevel gears or the like. The plurality of tower shaft gears 94 include a first tower shaft gear 94a coupled to the tower shaft 90 and a second tower shaft gear 94b coupled to the accessory gearbox input shaft 86. The first tower shaft gear 94a meshes with the second tower shaft gear 94b so that the rotation of the tower shaft 90 rotates the accessory gearbox input shaft 86. In this way, the tower shaft 90 transmits mechanical energy from the HP shaft 34 to one or more output shafts 88 through the accessory gearbox assembly 80, as described in further detail below. The one or more rotating components 55 can include the tower shaft 90 or a plurality of tower shaft gears 84.

[0051] The turbine engine 10 includes a lubrication system 100, which includes a main lubrication system 102, an auxiliary lubrication system 104, and a storage tank 106. The storage tank 106 ( Figure 2A and 2B Schematically shown in FIG. 1 ) is a reservoir in which lubricant is collected and stored. In some embodiments, the lubrication system 100 may include one or more tanks in which lubricant is stored. Preferably, the lubricant is oil. The lubricant may be any type of lubricant used to lubricate one or more rotating components 55 of the turbine engine 10 (e.g., a plurality of power gearbox gears 49 or one or more power gearbox bearings 53).

[0052] The main lubrication system 102 includes a main pump 108 and a main lubricant supply line 110. The main pump 108 is in fluid communication with the sump 106 and the main lubricant supply line 110. The main lubricant supply line 110 is in fluid communication with one or more rotating components 55 of the turbine engine 10. The main pump 108 pumps lubricant from the sump 106 to one or more rotating components 55 through the main lubricant supply line 110 for supplying lubricant to one or more rotating components 55, as described in further detail below. In some embodiments, the main pump 108 is a mechanical pump. For example, the main pump 108 is coupled to the accessory gearbox assembly 80 and is powered by the accessory gearbox assembly 80. The main pump 108 is coupled to the second output shaft 88b so that the rotation of the second output shaft 88b provides power for the main pump 108. In this way, the second output shaft 88b is the main pump shaft of the main pump 108. In some embodiments, the primary lubrication system 102 supplies lubricant from a sump 106 to one or more rotating components 55 without a pump, such as by gravity or by centrifugal force due to rotation of the planet carrier 51 in the planetary arrangement of the power gearbox gear assembly 47 .

[0053] The reservoir 106 is in fluid communication with one or more rotating components 55 so that lubricant can be removed from the reservoir 106, for example, via a purge line (for clarity, Figure 2A and 2B 106. In some embodiments, the lubrication system 100 includes a sump pump in fluid communication with the main lubrication system 102 and the auxiliary lubrication system 104. The sump pump pumps lubricant from the sump 106 to the main lubrication system 102 or the auxiliary lubrication system 104.

[0054] The auxiliary lubrication system 104 includes an auxiliary pump 120 and an auxiliary lubricant supply line 122. The auxiliary lubricant supply line 122 is in fluid communication with the sump 106 and one or more rotating components 55. Figure 2A and 2B Although depicted as being in fluid communication with the power gearbox assembly 46, the auxiliary lubricant supply line 122 may be in fluid communication with any of the one or more rotating components 55 of the turbine engine 10. Further, although the auxiliary lubricant supply line 122 is depicted as being in fluid communication with the power gearbox assembly 46, the auxiliary lubricant supply line 122 may be in fluid communication with any of the one or more rotating components 55 of the turbine engine 10. Figure 2A and 2B104, but the auxiliary lubricant supply line 122 may form a part of the main lubricant supply line 110. The auxiliary pump 120 is in fluid communication with the sump 106 and the auxiliary lubricant supply line 122. The auxiliary pump 120 is a mechanical pump that is powered by kinetic energy when the auxiliary lubrication system 104 is in operation, as described in further detail below. The auxiliary pump 120 is a variable displacement pump so that the displacement or amount of lubricant pumped per revolution of the input shaft of the auxiliary pump 120 varies when the auxiliary pump 120 is in operation. In this way, when the rotational speed of the input shaft of the auxiliary pump 120 decreases, the output of the amount of lubricant from the auxiliary pump 120 remains substantially constant, as described in further detail below.

[0055] The lubrication system 100 includes a kinetic energy storage system 130 that stores kinetic energy and releases kinetic energy to power the auxiliary lubrication system 104, as described in further detail below. The kinetic energy storage system 130 includes a flywheel 132 and an auxiliary pump shaft 134 that provides input power to the auxiliary pump 120. The flywheel 132 is a mechanical device that converts angular momentum to store kinetic energy (in the form of rotational energy) when the flywheel 132 rotates. For example, the flywheel 132 has a high angular momentum so that the flywheel 132 tends to keep rotating even after the rotational input (e.g., one or more output shafts 88 of the accessory gearbox assembly 80) has been removed. In this way, the flywheel 132 stores kinetic energy when the one or more output shafts 88 rotate the flywheel 132. In a non-limiting example, the flywheel 132 rotates at a maximum speed in the range of twenty thousand revolutions per minute to sixty-five thousand revolutions per minute (20,000RPM to 65,000RPM).

[0056] The kinetic energy storage system 130 includes one or more flywheel springs 136 and a clutch 138. The one or more flywheel springs 136 are coupled to the flywheel 132 and the static component. Figure 2A and 2B , the static component is the accessory gearbox housing 82 of the accessory gearbox assembly 80 such that one or more flywheel springs 136 are coupled to the accessory gearbox housing 82. When the auxiliary lubrication system 104 is in operation, the one or more flywheel springs 136 bias the flywheel 132 toward the auxiliary pump shaft 134 such that the flywheel 132 engages the auxiliary pump shaft 134, as described in further detail below.

[0057] The clutch 138 is drivingly coupled to the accessory gearbox assembly 80. The clutch 138 is coupled to one or more output shafts 88. In particular, the clutch 138 is coupled to the first output shaft 88a such that rotation of the first output shaft 88a rotates the clutch 138. The clutch 138 is an electromagnetic clutch that includes one or more magnets 139 that engage the flywheel 132 (e.g., when the auxiliary lubrication system 104 is not operating). Figure 2A In this way, the rotation of the clutch 138 causes the flywheel 132 to rotate. The controller 79 ( Figure 1 ) communicates with clutch 138 to engage ( Figure 2A ) or break away from ( Figure 2B ) flywheel 132, as further described below.

[0058] In operation, the LP shaft 36 rotates as described above and rotates the first power gearbox gear 49a. The first power gearbox gear 49a, which is meshed with the one or more second power gearbox gears 49b, rotates the one or more second power gearbox gears 49b about their corresponding rotational axes. The one or more second power gearbox gears 49b rotate relative to the one or more power gearbox bearings 53 within the planet carrier 51. When the power gearbox gear assembly 47 is a star arrangement, the one or more second power gearbox gears 49b, which are meshed with the third power gearbox gear 49c, rotate the third power gearbox gear 49c about the longitudinal centerline axis 12. In such an embodiment, the planet carrier 51 remains stationary so that the one or more second power gearbox gears 49b do not rotate about the longitudinal centerline axis 12. When the power gearbox gear assembly 47 is a planetary arrangement, the third power gearbox gear 49c is stationary in the planet carrier 51, and the one or more second power gearbox gears 49b rotate about the longitudinal centerline axis 12. When the power gearbox gear assembly 47 is a differential gear assembly, both the planet carrier 51 (eg, the one or more second power gearbox gears 49b) and the third power gearbox gear 49c rotate about the longitudinal centerline axis 12. In this manner, the one or more rotating members 55 rotate.

[0059] At the same time, the HP shaft 34 rotates and rotates the tower shaft 90, thereby rotating the accessory gearbox input shaft 86 and the plurality of accessory gearbox gears 84 of the accessory gearbox gear assembly 83. The rotation of the plurality of accessory gearbox gears 84 rotates the one or more output shafts 88. In particular, the rotation of the plurality of accessory gearbox gears 84 rotates the second output shaft 88b, thereby providing power to the main pump 108. In this manner, the main lubrication system 102 supplies lubricant to the one or more rotating components 55 to lubricate the one or more rotating components 55. During normal operation of the turbine engine 10, the main pump 108 pumps lubricant from the sump 106 and pumps the lubricant to the one or more rotating components 55 through the main lubricant supply line 110. The main lubrication system 102 supplies lubricant to the one or more rotating components 55. The lubricant is discharged from the one or more rotating components 55 and enters the sump 106. During normal operation of turbine engine 10, lubricant in sump 106 is returned through primary lubrication system 102 so that primary lubrication system 102 continuously supplies lubricant to one or more rotating components 55. In this manner, lubricant may be reused to lubricate one or more rotating components 55.

[0060] When primary lubrication system 102 is operating, such as when turbine engine 10 is operating under normal operation, auxiliary lubrication system 104 is not operating. Figure 2A ), the clutch 138 engages the flywheel 132, so that the flywheel 132 is disengaged from the auxiliary pump 120. In this way, the auxiliary pump 120 is prevented from pumping lubricant when the auxiliary lubrication system 104 is not operating. The force of the one or more magnets 139 of the clutch 138 is greater than the force of the one or more flywheel springs 136, so that the clutch 138 overcomes the biasing force of the one or more flywheel springs 136 to pull the flywheel 132 away from the auxiliary pump 120, so that the flywheel 132 does not engage the auxiliary pump 120. The controller 79 ( Figure 1 ) controls the clutch 138 to engage the flywheel 132. In some embodiments, the controller 79 controls the clutch 138 to engage the flywheel 132 by providing an electrical signal to the clutch 138. In some embodiments, the controller 79 controls the clutch 138 to engage the flywheel 132 based on a rotational speed of at least one of the HP shaft 34, the LP shaft 36, or the propeller shaft 45. For example, when a rotational speed of at least one of the HP shaft 34, the LP shaft 36, or the propeller shaft 45 is greater than a rotational speed threshold, the controller 79 controls the clutch 138 to engage the flywheel 132. In some embodiments, the clutch 138 engages the flywheel 132 based on a pressure of the lubricant in the main lubrication system 102. For example, when a pressure of the lubricant in the main lubrication system 102 is greater than a main pressure threshold, the clutch 138 engages the flywheel 132.

[0061] When the clutch 138 engages the flywheel 132, the accessory gearbox assembly 80 causes the flywheel 132 to rotate. For example, rotation from the HP shaft 34 causes the tower shaft 90 to rotate, thereby rotating the accessory gearbox input shaft 86 and the plurality of accessory gearbox gears 84. The rotation of the plurality of accessory gearbox gears 84 causes the one or more output shafts 88 to rotate, thereby rotating the clutch 138 and the flywheel 132. As the flywheel 132 rotates, the flywheel 132 stores kinetic energy (referred to as stored kinetic energy) in the flywheel 132 as angular momentum. In this manner, the flywheel 132 will tend to continue to rotate after the clutch 138 disengages the flywheel 132. For example, when the flywheel 132 is no longer being rotated by the accessory gearbox assembly 80, the flywheel 132 will continue to rotate.

[0062] In some cases, the main lubrication system 102 may be unable to provide lubricant to one or more rotating components 55. For example, the main lubrication system 102 may be unable to pressurize lubricant to supply lubricant to one or more rotating components 55 during wind-driven rotation when the turbine engine 10 is shut down, or during a turbine engine 10 failure or a main lubrication system 102 (e.g., main pump 108) failure in flight. In this case, the wind-driven rotation may cause the shafts of the turbine engine 10 (e.g., propeller shaft 45, HP shaft 34, and LP shaft 36) to rotate, thereby causing one or more rotating components 55 to continue to rotate. As described above, if there is not enough lubricant supplied to one or more rotating components 55, one or more rotating components 55 (e.g., multiple power gearbox gears 49 or one or more power gearbox bearings 53) may become damaged.

[0063] Therefore, during this situation, the auxiliary lubrication system 104 is activated to supply lubricant to one or more rotating components 55, such as Figure 2B The clutch 138 disengages the flywheel 132, causing the flywheel 132 to engage the auxiliary pump shaft 134 (as shown in FIG. Figure 2B134 ) to power the auxiliary pump 120. For example, when the clutch 138 is disengaged from the flywheel 132, one or more flywheel springs 136 bias the flywheel 132 toward the auxiliary pump 120 to engage the auxiliary pump shaft 134. As detailed above, when the flywheel 132 is disengaged from the accessory gearbox assembly 80, the flywheel 132 continues to rotate. When the flywheel 132 engages the auxiliary pump shaft 134, the rotation of the flywheel 132 rotates the auxiliary pump shaft 134, thereby powering the auxiliary pump 120. In this way, the flywheel 132 releases stored kinetic energy to power the auxiliary pump 120. The auxiliary pump 120 pumps lubricant from the sump 106 to the one or more rotating components 55 through the auxiliary lubricant supply line 122. In this way, when the main lubrication system 102 is unable to supply lubricant to the one or more rotating components 55, the auxiliary lubrication system 104 supplies lubricant to the one or more rotating components 55. The lubricant is discharged from the one or more rotating components 55 and enters the sump 106. When the auxiliary lubrication system 104 is in operation, the lubricant in the sump 106 is returned through the auxiliary lubrication system 104 so that the auxiliary lubrication system 104 continuously supplies lubricant to the one or more rotating components 55 when the kinetic energy storage system 130 releases the stored kinetic energy.

[0064] When the flywheel 132 engages the auxiliary pump 120, the flywheel 132 rotates at a high speed (e.g., 20,000 RPM to 65,000 RPM). In this way, the kinetic energy stored by the flywheel 132 is transferred to the auxiliary pump 120 (e.g., through the auxiliary pump shaft 134) to provide power for the auxiliary pump 120. In this condition, the displacement of the auxiliary pump 120 is low, so that the auxiliary pump 120 pumps lubricant at a specific output. As the flywheel 132 continues to rotate, the speed of the flywheel 132 decreases, so that the kinetic energy stored in the flywheel 132 dissipates over time. In order to account for the decrease in the speed of the flywheel 132, the auxiliary pump 120 increases the displacement of the lubricant, thereby maintaining the lubricant output substantially constant even when the speed of the flywheel 132 decreases. In this way, when the kinetic energy stored in the flywheel 132 is dissipated, the auxiliary pump 120 supplies lubricant at a substantially constant mass flow rate. This configuration prevents the auxiliary pump 120 from supplying too much lubricant to one or more rotating components 55 when the flywheel 132 initially engages the auxiliary pump 120, and prevents the auxiliary pump 120 from supplying too little lubricant to one or more rotating components 55 as the flywheel 132 continues to rotate and kinetic energy dissipates (e.g., when less power is supplied to the auxiliary pump 120).

[0065] Controller 79( Figure 1) controls the clutch 138 to disengage the flywheel 132 from the accessory gearbox assembly 80. In some embodiments, when the clutch 138 does not receive an electrical signal from the controller 79, the clutch 138 disengages the flywheel 132. In some embodiments, the controller 79 controls the clutch 138 to disengage the flywheel 132 based on a rotational speed of at least one of the HP shaft 34, the LP shaft 36, or the propeller shaft 45. For example, when the rotational speed of at least one of the HP shaft 34, the LP shaft 36, or the propeller shaft 45 is less than a rotational speed threshold, the controller 79 controls the clutch 138 to disengage the flywheel 132. In some embodiments, the controller 79 controls the clutch 138 to disengage the flywheel 132 based on a pressure of lubricant in the main lubrication system 102. For example, when the pressure of lubricant in the main lubrication system 102 is less than a main pressure threshold, the controller 79 controls the clutch 138 to disengage the flywheel 132. In this way, when the auxiliary lubrication system 104 is activated, the clutch 138 disengages the flywheel 132, so that the flywheel 132 engages the auxiliary pump 120 to provide power to the auxiliary pump 120.

[0066] Figure 3 is a schematic diagram of a turbine engine 10 ( Figure 1 ) is a schematic cross-sectional view of a power gearbox assembly 46. Figure 3 As shown, the one or more second power gearbox gears 49b include three second power gearbox gears 49b. However, the one or more second power gearbox gears 49b may include any number of second power gearbox gears 49b as desired. Each second power gearbox gear 49b has a corresponding power gearbox bearing 53 associated therewith, so that there are three power gearbox bearings 53. For example, the one or more power gearbox bearings 53 include a first power gearbox bearing 53a, a second power gearbox bearing 53b, and a third power gearbox bearing 53c.

[0067] The auxiliary lubricant supply line 122 includes one or more lubricant branch lines 125 in fluid communication with one or more power gearbox bearings 53. In this manner, the lubrication system 100 ( Figure 2A and 2B) directly supplies lubricant to one or more power gearbox bearings 53. For example, the one or more lubricant branch lines 125 include a first lubricant branch line 125a in fluid communication with the first power gearbox bearing 53a, a second lubricant branch line 125b in fluid communication with the second power gearbox bearing 53b, and a third lubricant branch line 125c in fluid communication with the third power gearbox bearing 53c. Lubricant flows from the auxiliary lubricant supply line 122 to the first power gearbox bearing 53a through the first lubricant branch line 125a. Lubricant flows from the auxiliary lubricant supply line 122 to the second power gearbox bearing 53b through the second lubricant branch line 125b. Lubricant flows from the auxiliary lubricant supply line 122 to the third power gearbox bearing 53c through the third lubricant branch line 125c. Although the one or more lubricant branch lines 125 are depicted as branch lines of the auxiliary lubricant supply line 122, the one or more lubricant branch lines 125 may also be branch lines of the main lubricant supply line 110 ( Figure 2A and 2B ) branch pipeline.

[0068] Thus, when the turbine engine 10 is shut down or otherwise spinning under wind power, the auxiliary lubrication system 104 supplies lubricant to one or more rotating components 55. Figure 2A and 2B ) Ensure that the auxiliary pump 120 ( Figure 2A and 2B ) operates to pump lubricant to one or more rotating components 55 without being constrained by the propeller 38 ( Figure 2A and 2B ) during wind-driven rotation (e.g., whether the propeller is rotating clockwise or counterclockwise). Compared to an auxiliary lubrication system without the benefit of the present disclosure, the kinetic energy storage system 130 is not constrained by the propeller shaft 45 ( Figure 2A and 2B ) or other shafts of the turbine engine 10, the auxiliary lubrication system 104 ( Figure 2A and 2B ) complexity.

[0069] Further aspects of the disclosure are provided by the subject matter of the following clauses.

[0070] A lubrication system for a turbine engine, the turbine engine comprising a propeller and one or more rotating parts, the lubrication system comprising: a tank in which lubricant is stored; a main lubrication system, which supplies the lubricant from the tank to the one or more rotating parts during normal operation of the turbine engine; an auxiliary lubrication system, the auxiliary lubrication system comprising an auxiliary pump, the auxiliary pump comprising an auxiliary pump shaft; and a kinetic energy storage system, the kinetic energy storage system comprising a flywheel, when the propeller is rotated by wind, the flywheel engages the auxiliary pump shaft to power the auxiliary pump, so that the auxiliary pump pumps the lubricant from the tank to the one or more rotating parts.

[0071] A lubrication system according to any preceding clause, wherein the auxiliary pump is a variable displacement pump which increases the displacement of the lubricant from the auxiliary pump as the rotational speed of the flywheel decreases.

[0072] A lubrication system as described in any preceding clause, the kinetic energy storage system further comprising a clutch that engages the flywheel during normal operation of the turbine engine such that rotation of the clutch causes the flywheel to rotate and store kinetic energy.

[0073] A lubrication system as described in any preceding clause, wherein when the propeller is wind-driven, the clutch disengages the flywheel, causing the flywheel to engage the auxiliary pump shaft and release the stored kinetic energy to power the auxiliary pump.

[0074] A lubrication system according to any preceding clause, the kinetic energy storage system further comprising one or more flywheel springs, the one or more flywheel springs biasing the flywheel towards the auxiliary pump shaft when the propeller is wind-driven.

[0075] A lubrication system according to any preceding clause, the clutch being an electromagnetic clutch controlled to engage the flywheel during normal operation of the turbine engine and to disengage the flywheel when the propeller is wind-driven.

[0076] A lubrication system as described in any preceding clause, the turbine engine further comprising an accessory gearbox assembly having a plurality of accessory gearbox gears, the flywheel being drivingly coupled to the plurality of accessory gearbox gears.

[0077] A lubrication system as described in any preceding clause, the turbine engine comprising a high pressure shaft and a low pressure shaft, and the plurality of accessory gearboxes being gear drivingly coupled to at least one of the high pressure shaft or the low pressure shaft.

[0078] A lubrication system according to any preceding clause, the main lubrication system comprising a main pump for pumping the lubricant from the sump to the one or more rotating components during normal operation of the turbine engine.

[0079] A lubrication system as described in any preceding clause, the main pump being drivingly coupled to the plurality of accessory gearbox gears.

[0080] A method of operating a lubrication system according to any of the preceding clauses, the method comprising: supplying the lubricant to the one or more rotating components through the main lubrication system during normal operation of the turbine engine; starting the auxiliary lubrication system by engaging the flywheel with an auxiliary pump shaft when the propeller is wind-driven, the flywheel rotating to power the auxiliary pump; and pumping the lubricant from the storage tank to the one or more rotating components with the auxiliary pump when the flywheel powers the auxiliary pump.

[0081] A method according to any preceding clause, the auxiliary pump being a variable displacement pump, and the method further comprising increasing the displacement of the lubricant from the auxiliary pump as the rotational speed of the flywheel decreases.

[0082] A method according to any preceding clause, the kinetic energy storage system further comprising a clutch, and the method further comprising, during normal operation of the turbine engine, engaging the flywheel with the clutch such that rotation of the clutch causes the flywheel to rotate and store kinetic energy.

[0083] The method according to any of the preceding clauses further comprises: disengaging the flywheel from the clutch when the propeller is rotated by wind power; and engaging the flywheel with the auxiliary pump shaft when the flywheel is disengaged by the clutch, so that the flywheel releases the stored kinetic energy to power the auxiliary pump.

[0084] A method according to any preceding clause, the kinetic energy storage system further comprising one or more flywheel springs, and the method further comprising biasing the flywheel towards the auxiliary pump shaft with the one or more flywheel springs when the propeller is wind-driven.

[0085] A method according to any preceding clause, the clutch being an electromagnetic clutch, and the method further comprising controlling the electromagnetic clutch to engage the flywheel during normal operation of the turbine engine and to disengage the flywheel when the propeller is wind-driven.

[0086] A method according to any preceding clause, the turbine engine further comprising an accessory gearbox assembly having a plurality of accessory gearbox gears, and the method further comprising driving the flywheel with the plurality of accessory gearbox gears to rotate the flywheel during normal operation of the turbine engine.

[0087] A method according to any preceding clause, the turbine engine comprising a high pressure shaft and a low pressure shaft, and the method further comprising driving the plurality of accessory gearbox gears via at least one of the high pressure shaft or the low pressure shaft.

[0088] A method according to any preceding clause, the primary lubrication system comprising a main pump, and the method further comprising pumping the lubricant from the sump to the one or more rotating components with the main pump during normal operation of the turbine engine.

[0089] A method according to any preceding clause, further comprising driving the main pump with the plurality of accessory gearbox gears.

[0090] A lubrication system as described in any preceding clause, the turbine engine comprising a power gearbox assembly having a plurality of power gearbox gears.

[0091] A lubrication system as claimed in any preceding clause, wherein the one or more rotating components are one or more power gearbox bearings of the power gearbox assembly.

[0092] A lubrication system according to any preceding clause, wherein the one or more power gearbox bearings are journal bearings.

[0093] The lubrication system of any preceding clause, the turbine engine further comprising a tower shaft coupled to at least one of the high pressure shaft or the low pressure shaft.

[0094] A lubrication system as described in any preceding clause, the accessory gearbox assembly further comprising an accessory gearbox input shaft and one or more output shafts.

[0095] A lubrication system as described in any preceding clause, the accessory gearbox input shaft being drivingly coupled to the tower shaft.

[0096] A lubrication system as described in any preceding clause, the accessory gearbox input shaft being drivingly coupled to the tower shaft via a tower shaft gear assembly.

[0097] A lubrication system as described in any preceding clause, the accessory gearbox assembly having an accessory gearbox housing, the plurality of accessory gearbox gears being disposed within the accessory gearbox housing.

[0098] A lubrication system as described in any preceding clause, one or more flywheel springs coupled to the accessory gearbox housing and the flywheel.

[0099] A lubrication system as described in any preceding clause, the plurality of accessory gearbox gears comprising a first accessory gearbox gear, a second accessory gearbox gear and a third accessory gearbox gear.

[0100] A lubrication system as described in any preceding clause, the accessory gearbox input shaft being coupled to the first accessory gearbox gear.

[0101] A lubrication system as described in any preceding clause, wherein the one or more output shafts comprises a first output shaft coupled to the clutch.

[0102] A lubrication system as described in any preceding clause, wherein the one or more output shafts comprises a second output shaft coupled to the main pump.

[0103] A lubrication system as described in any preceding clause, the first output shaft being coupled to the second accessory gearbox gear.

[0104] A lubrication system as described in any preceding clause, wherein the second output shaft is coupled to the third accessory gearbox gear.

[0105] A lubrication system as claimed in any preceding clause, the plurality of accessory gearbox gears further comprising a fourth accessory gearbox gear disposed between the second accessory gearbox gear and the third accessory gearbox gear.

[0106] A lubrication system as claimed in any preceding clause, the auxiliary lubrication system comprising an auxiliary lubricant supply line in fluid communication with the sump and the one or more rotating components.

[0107] A lubrication system according to any preceding clause, the auxiliary lubricant supply line comprising one or more auxiliary lubricant branch lines, each of the one or more auxiliary lubricant branch lines being coupled to a different one of the one or more rotating components.

[0108] A lubrication system as claimed in any preceding clause, the main lubrication system comprising a main lubricant supply line in fluid communication with the sump and the one or more rotating components.

[0109] A turbine engine comprising a propeller and a core turbine engine having a shaft, the propeller being drivingly coupled to the shaft. The turbine engine comprises a lubrication system according to any preceding clause.

[0110] A method as in any preceding clause, the lubrication system being a lubrication system as in any preceding clause.

[0111] Although the foregoing description is directed to the preferred embodiments of the present disclosure, other changes and modifications are apparent to those skilled in the art and may be made without departing from the spirit or scope of the present disclosure. In addition, the 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 lubrication system for a turbine engine, the turbine engine comprising a propeller and one or more rotating parts, characterized in that: The lubrication system comprises: a reservoir storing lubricant therein; a primary lubrication system that supplies the lubricant from the reservoir to the one or more rotating components during normal operation of the turbine engine; an auxiliary lubrication system, the auxiliary lubrication system comprising an auxiliary pump, the auxiliary pump comprising an auxiliary pump shaft; and A kinetic energy storage system includes a flywheel, which, when the propeller is wind-driven, engages the auxiliary pump shaft to power the auxiliary pump so that the auxiliary pump pumps the lubricant from the reservoir to the one or more rotating components.

2. The lubrication system according to claim 1, characterized in that: The auxiliary pump is a variable displacement pump that increases displacement of the lubricant from the auxiliary pump as the rotational speed of the flywheel decreases.

3. The lubrication system according to claim 1, characterized in that: Wherein the kinetic energy storage system further includes a clutch that engages the flywheel during normal operation of the turbine engine such that rotation of the clutch causes the flywheel to rotate and store kinetic energy.

4. The lubrication system according to claim 3, characterized in that: When the propeller rotates due to wind force, the clutch disengages the flywheel, causing the flywheel to engage the auxiliary pump shaft and release the stored kinetic energy to power the auxiliary pump.

5. The lubrication system according to claim 4, characterized in that: The kinetic energy storage system further comprises one or more flywheel springs, which bias the flywheel towards the auxiliary pump shaft when the propeller rotates due to wind force.

6. The lubrication system according to claim 4, characterized in that: The clutch is an electromagnetic clutch that is controlled to engage the flywheel during normal operation of the turbine engine and to disengage the flywheel when the propeller is rotated by wind.

7. The lubrication system according to claim 1, characterized in that: Wherein the turbine engine further includes an accessory gearbox assembly having a plurality of accessory gearbox gears, the flywheel being drivingly coupled to the plurality of accessory gearbox gears.

8. The lubrication system according to claim 7, characterized in that: The turbine engine includes a high pressure shaft and a low pressure shaft, and the plurality of accessory gearboxes are gear-drivingly coupled to at least one of the high pressure shaft or the low pressure shaft.

9. The lubrication system according to claim 7, characterized in that: The main lubrication system includes a main pump that pumps the lubricant from the sump to the one or more rotating components during normal operation of the turbine engine.

10. The lubrication system according to claim 9, characterized in that: Wherein the main pump is drivingly coupled to the plurality of accessory gearbox gears.

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