Gearbox assembly

Abstract

A gearbox assembly (200) includes a planet carrier (210), a planet gear (206) disposed within the planet carrier, one or more roller bearings (244) disposed within the planet gear, the one or more roller bearings including a plurality of rolling elements (245), and an integral pin (240) disposed within the planet carrier and extending through the planet gear. The integral pin includes one or more pin shoulders (272) extending from the integral pin. The plurality of rolling elements are disposed axially between the one or more pin shoulders and radially between the integral pin and the planet gear. The one or more pin shoulders axially constrain the plurality of rolling elements. The planet gear rotates about the one or more roller bearings with respect to the integral pin.

Description

GEARBOX ASSEMBLYTECHNICAL FIELD

[0001] The present disclosure relates generally to gearbox assemblies for engines, such as turbine engines.BACKGROUND

[0002] An engine, such as a turbine engine, may generally include a fan and a turbomachine arranged in flow communication with one another. The engine may include one or more gearbox assemblies.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, wherein like reference numbers generally indicate identical, functionally similar, and / or structurally similar elements.

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

[0005] FIG. 2 is a schematic, cross-sectional side view of a gearbox assembly for a turbine engine, taken along a longitudinal centerline axis of the turbine engine, according to the present disclosure.

[0006] FIG. 3 is detailed schematic, cross-sectional view of the gearbox assembly of FIG. 2 illustrating details of an integral pin of the gearbox assembly, taken at detail 249 in FIG.2, according to the present disclosure.

[0007] FIG. 4 is an enlarged schematic, cross-sectional view of a portion of an integral pin for a gearbox assembly, taken along a longitudinal centerline axis of the integral pin, according to another embodiment.DETAILED DESCRIPTION

[0008] Additional features, advantages, and embodiments of the present disclosure are set forth or apparent from a consideration of the following detailed description, drawings, and claims. Moreover, both the foregoing summary of the present disclosure and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the disclosure as claimed.

[0009] Various embodiments of the present disclosure are discussed in detail below.While specific embodiments are discussed, this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without departing from the spirit and the 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 signify location or importance of the individual components.

[0011] The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows.

[0012] The terms “forward” and “aft” refer to relative positions within an engine or a vehicle, and refer to the normal operational attitude of the engine or the vehicle. For example, with regard to an engine, forward refers to a position closer to an engine inlet and aft refers to a position closer to an engine nozzle or an exhaust.

[0013] As used herein, the terms “low” and “high,” or their respective comparative degrees (e.g., “lower” and “higher”, where applicable), when used with compressor, turbine, shaft, fan, turbine engine components, or aircraft components, each refers to relative pressures, relative speeds, relative temperatures, and / or relative power outputs within an engine unlessotherwise specified. For example, a “low speed” refers to a speed that is lower than a “high speed.” The terms “low,” or “high” in such aforementioned terms may additionally, or alternatively, be understood as relative to minimum allowable speeds, pressures, powers, or temperatures, or minimum or maximum allowable speeds, pressures, powers, or temperatures relative to normal, desired, steady state, etc., operation of the engine or of the aircraft.

[0014] The terms “coupled,” “fixed,” “attached,” “connected,” and the like, refer to both direct coupling, fixing, attaching, or connecting, as well as indirect coupling, fixing, attaching, or connecting through one or more intermediate components or features, unless otherwise specified herein.

[0015] The singular forms “a,” “an,” and “the” include plural referencesunless the context clearly dictates otherwise.

[0016] As used herein, the terms “axial” and “axially” refer to directions and orientations that extend substantially parallel to a centerline of the engine. Moreover, the terms “radial” and “radially” refer to directions and orientations that extend substantially perpendicular to the centerline of the engine. In addition, as used herein, the terms “circumferential” and “circumferentially” refer to directions and orientations that extend arcuately about the centerline of the engine.

[0017] Approximating language, as used herein throughout the specification and claims, is applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” “generally,” and “substantially” is not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value, or the precision of the methods or the machines for constructing the components and / or the systems or manufacturingthe components and / or the systems. For example, the approximating language may refer to being within a one, a two, a four, a ten, a fifteen, or a twenty percent margin in either individual values, range(s) of values and / or endpoints defining range(s) of values.

[0018] The present disclosure provides for engines, such as unducted single fan (USF) engines, with a high-speed low-pressure turbine and a variable pitch propeller or a fan. USF engines provide for a high power rating. Such engines can be configured as a geared engine that includes a power gearbox utilized to transfer power from a turbine shaft, such as a low-pressure shaft, to the propeller or the fan. Power gearboxes can also be utilized in other sections of the engine. In such high power engines, however, a high gear ratio is needed to drive the propeller at the required speed and torque. For example, the gear ratio of the power gearbox between the low-pressure turbine and the propeller can be in a range of 6:1 and 12:1. While the present disclosure refers to USF engines, the embodiments detailed herein may be utilized for other types of turbine engines with high gear ratios (e.g., gear ratios greater than or equal to 6:1). Such power gearboxes enable higher speeds and higher torques as compared to power gearboxes with lower gear ratio (e.g., gear ratios less than 6:1).

[0019] Power gearboxes may include a sun gear, a plurality of planet gears, and a ring gear. The sun gear meshes with the plurality of planet gears and the plurality of planet gears mesh with the ring gear. In operation, the power gearbox transfers the torque transmitted from the turbine shaft operating at a first speed to a fan shaft rotating at a second, lower speed. The sun gear may be coupled to the low-pressure shaft of the turbine rotating at the first speed. In a planet configuration of the power gearbox, the plurality of planet gears, intermeshed with the sun gear, transfer this torque to the fan shaft through a planet carrier. The planet carrier contains the plurality of planet gears therein. In a star configuration, the ring gear is coupled to the fan shaft.In either configuration, the plurality of planet gears may include compound gears such that theplurality of planet gears each includes a first stage and a second stage. The first stage is meshed with the sun gear and the second stage is meshed with the ring gear. A pin is inserted into the planet carrier and through the planet gears, and one or more bearings are positioned between the pin and the planet gears to enable the planet gears to rotate with respect to the pin.

[0020] As engines increase in power and thrust, the torque and speeds described becomes more challenging to accommodate, while at the same time, minimizing the overall weight of the engine while increasing engine efficiency of the engine. One way to minimize overall weight of the engine is to minimize the weight of the power gearbox by making the power gearbox smaller. The present disclosure reduces the size, and, thus, the weight of the power gearbox by providing an integral pin that couples to the planet carrier of the gearbox assembly and provides the inner race of the roller bearings. For example, the integral pin integrates the function of the inner race of the roller bearings and of the pin that couples the planet gears to the planet carrier in order to reduce a number of parts, and to enable high gear ratio power gearboxes for such high power engines. The reduction in the number of parts provides for a reduction in a number of contact surfaces, thereby reducing the risk of surface wear and / or reciprocal displacement, and improving overall system reliability. Accordingly, the integral pin of the present disclose helps to reduce the size and the weight of the power gearbox, thereby reducing the size and the weight of the turbine engine and increasing an efficiency of the turbine engine, while improving reliability of the power gearbox, as compared to power gearboxes and turbine engines without the benefit of the present disclosure.

[0021] Referring now to the drawings, FIG. 1 is a schematic, cross-sectional diagram of a turbine engine 10, taken along a centerline axis of the turbine engine 10, according to the present disclosure. Particularly, FIG. 1 provides an aviation three-stream turbofan engine also referred to as a “three-stream engine.” The turbine engine 10 of FIG. 1 can be mounted to an aerialvehicle, such as a fixed-wing aircraft, and can produce thrust for propulsion of the aerial vehicle.The turbine engine 10 is a “three-stream engine” in that its architecture provides three distinct streams of thrust-producing airflow during operation, as detailed further below.

[0022] As shown in FIG. 1 , the turbine engine 10 defines an axial direction A, a radial direction R, and a circumferential direction C. Moreover, the turbine engine 10 defines an axial centerline or a longitudinal centerline axis 12 that extends along the axial direction A. In general, the axial direction A extends parallel to the longitudinal centerline axis 12, the radial direction R extends outward from, and inward to, the longitudinal centerline axis 12 in a direction orthogonal to the axial direction A, and the circumferential direction C extends three hundred sixty degrees (360°) around the longitudinal centerline axis 12. The turbine engine 10 extends between a forward end 14 and an aft end 16, e.g., along the axial direction A.

[0023] The turbine engine 10 includes a turbomachine 18 and a fan section 50 positioned upstream thereof. Generally, the turbomachine 18 includes, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. Particularly, as shown in FIG. 1 , the turbomachine 18 includes an engine core 20 and a core cowl 22 that annularly surrounds the turbomachine 18. The turbomachine 18 and the core cowl 22 define a core inlet 24 that is annular. The core cowl 22 further encloses and supports a booster or a low pressure (LP) compressor 26 for pressurizing the air that enters the turbomachine 18 through core inlet 24. The engine core 20 includes a high pressure (HP) compressor 28, a combustor 30, and a high pressure (HP) turbine 32. The HP compressor 28 receives pressurized air from the LP compressor 26 and further increases the pressure of the air. The pressurized air flows downstream to the combustor 30 where fuel is injected into the pressurized air and ignited to raise the temperature and the energy level of the pressurized air, thereby generating combustion gases.

[0024] The combustion gases flow from the combustor 30 downstream to the HP turbine 32. The HP turbine 32 drives the HP compressor 28 through a first shaft, also referred to as a high pressure (HP) shaft 36. In this regard, the HP turbine 32 is drivingly coupled with the HP compressor 28. The combustion gases then flow to a low pressure (LP) turbine 34. The LP turbine 34 drives the LP compressor 26 and components of the fan section 50 through a second shaft, also referred to as a low pressure (LP) shaft 38. In this regard, the LP turbine 34 is drivingly coupled with the LP compressor 26 and components of the fan section 50. The LP shaft 38 is coaxial with the HP shaft 36 in the embodiment of FIG. 1. After driving each of the HP turbine 32 and the LP turbine 34, the combustion gases exit the turbomachine 18 through a core exhaust nozzle 40 to produce propulsive thrust. Accordingly, the turbomachine 18 defines a core flowpath, also referred to as a core duct 42, that extends between the core inlet 24 and the core exhaust nozzle 40. The core duct 42 is an annular duct positioned generally inward of the core cowl 22 along the radial direction R.

[0025] The fan section 50 includes a primary fan 52. For the embodiment of FIG. 1 , the primary fan 52 is an open rotor fan, also referred to as an unducted fan. However, in other embodiments, the primary fan 52 maybe ducted, e.g., by a fan casing or a nacelle circumferentially surrounding the primary fan 52. The primary fan 52 includes an array of fan blades 54 (only one shown in FIG. 1 ). The fan blades 54 are rotatable about the longitudinal centerline axis 12 via a fan shaft 56. As shown in FIG. 1 , the fan shaft 56 is coupled with the LP shaft 38 via a speed reduction gearbox, also referred to as a gearbox assembly 55, e.g., in an indirect-drive configuration. The gearbox assembly 55 is shown schematically in FIG. 1. The gearbox assembly 55 is coupled to the turbine engine 10 by a static structure, as detailed further below. The gearbox assembly 55 includes a plurality of gears for adjusting the rotational speedof the fan shaft 56 and, thus, the primary fan 52 relative to the LP shaft 38 to a more efficient rotational fan speed.

[0026] The fan blades 54 can be arranged in equal spacing around the longitudinal centerline axis 12. Each fan blade 54 has a root and a tip, and a span defined therebetween. Each fan blade 54 defines a central blade axis 57. For the embodiment of FIG. 1 , each fan blade 54 of the primary fan 52 is rotatable about their respective central blade axis 57, e.g., in unison with one another. One or more actuators 58 are controlled to pitch the fan blades 54 about their respective central blade axis 57. In other embodiments, each fan blade 54 is fixed or is unable to be pitched about the central blade axis 57.

[0027] The fan section 50 further includes a fan guide vane array 60 that includes fan guide vanes 62 (only one shown in FIG. 1) disposed around the longitudinal centerline axis 12. For the embodiment of FIG. 1 , the fan guide vanes 62 are not rotatable about the longitudinal centerline axis 12. Each fan guide vane 62 has a root and a tip, and a span defined therebetween. The fan guide vanes 62 can be unshrouded as shown in FIG. 1 or can be shrouded, e.g., by an annular shroud spaced outward from the tips of the fan guide vanes 62 along the radial direction R. Each fan guide vane 62 defines a central vane axis 64. For the embodiment of FIG. 1 , each fan guide vane 62 of the fan guide vane array 60 is rotatable about their respective central vane axis 64, e.g., in unison with one another. One or more actuators 66 are controlled to pitch the fan guide vanes 62 about their respective central vane axis 64. In other embodiments, each fan guide vane 62 is fixed or is unable to be pitched about the central vane axis 64. The fan guide vanes 62 are mounted to a fan cowl 70.

[0028] The fan cowl 70 annularly encases at least a portion of the core cowl 22 and is generally positioned outward of the core cowl 22 along the radial direction R. Particularly, a downstream section of the fan cowl 70 extends over a forward portion of the core cowl 22 todefine a fan flowpath, also referred to as a fan duct 72. Incoming air enters through the fan duct72 through a fan duct inlet 76 and exits through a fan exhaust nozzle 78 to produce propulsive thrust. The fan duct 72 is an annular duct positioned generally outward of the core duct 42 along the radial direction R. The fan cowl 70 and the core cowl 22 are connected together and supported by a plurality of struts 74 (only one shown in FIG. 1) that extend substantially radially and are circumferentially spaced about the longitudinal centerline axis 12. The plurality of struts 74 are each aerodynamically contoured to direct air flowing thereby. Other struts in addition to the plurality of struts 74 can be used to connect and support the fan cowl 70 and / or the core cowl 22.

[0029] The turbine engine 10 also defines or includes an inlet duct 80. The inlet duct 80 extends between an engine inlet 82 and the core inlet 24 and the fan duct inlet 76. The engine inlet 82 is defined generally at the forward end of the fan cowl 70 and is positioned between the primary fan 52 and the fan guide vane array 60 along the axial direction A. The inlet duct 80 is an annular duct that is positioned inward of the fan cowl 70 along the radial direction R. Air flowing downstream along the inlet duct 80 is split, not necessarily evenly, into the core duct 42 and the fan duct 72 by a splitter 44 of the core cowl 22. The inlet duct 80 is wider than the core duct 42 along the radial direction R. The inlet duct 80 is also wider than the fan duct 72 along the radial direction R.

[0030] The fan section 50 also includes a mid-fan 90. The mid-fan 90 includes a plurality of mid-fan blades 92 (only one shown in FIG. 1). The plurality of mid-fan blades 92 are rotatable, e.g., about the longitudinal centerline axis 12. The mid-fan 90 is drivingly coupled with the LP turbine 34 via the LP shaft 38. The plurality of mid-fan blades 92 can be arranged in equal circumferential spacing about the longitudinal centerline axis 12. The plurality of mid-fan blades 92 are annularly surrounded (e.g., ducted) by the fan cowl 70. In this regard, the mid-fan90 is positioned inward of the fan cowl 70 along the radial direction R. The mid-fan 90 is positioned within the inlet duct 80 upstream of both the core duct 42 and the fan duct 72.

[0031] Accordingly, air flowing through the inlet duct 80 flows across the plurality of mid-fan blades 92 and is accelerated downstream thereof. At least a portion of the air accelerated by the mid-fan blades 92 flows into the fan duct 72 and is ultimately exhausted through the fan exhaust nozzle 78 to produce propulsive thrust. Also, at least a portion of the air accelerated by the plurality of mid-fan blades 92 flows into the core duct 42 and is ultimately exhausted through the core exhaust nozzle 40 to produce propulsive thrust. Generally, the midfan 90 is a compression device positioned downstream of the engine inlet 82. The mid-fan 90 is operable to accelerate air into the fan duct 72, also referred to as a secondary bypass passage.

[0032] During operation of the turbine engine 10, an initial airflow or an incoming airflow passes through the fan blades 54 of the primary fan 52 and splits into a first airflow and a second airflow. The first airflow bypasses the engine inlet 82 and flows generally along the axial direction A outward of the fan cowl 70 along the radial direction R. The first airflow accelerated by the fan blades 54 passes through the fan guide vanes 62 and continues downstream thereafter to produce a primary propulsion stream or a first thrust stream SI . A majority of the net thrust produced by the turbine engine 10 is produced by the first thrust stream SI . The second airflow enters the inlet duct 80 through the engine inlet 82.

[0033] The second airflow flowing downstream through the inlet duct 80 flows through the plurality of mid-fan blades 92 of the mid-fan 90 and is consequently compressed. The second airflow flowing downstream of the mid-fan 90 is split by the splitter 44 located at the forward end of the core cowl 22. Particularly, a portion of the second airflow flowing downstream of the mid-fan 90 flows into the core duct 42 through the core inlet 24. The portion of the second airflow that flows into the core duct 42 is progressively compressed by the LPcompressor 26 and the HP compressor 28, and is ultimately discharged into the combustion section. The discharged pressurized air stream flows downstream to the combustor 30 where fuel is introduced to generate combustion gases or products.

[0034] The combustor 30 defines an annular combustion chamber that is generally coaxial with the longitudinal centerline axis 12. The combustor 30 receives pressurized air from the HP compressor 28 via a pressure compressor discharge outlet. A portion of the pressurized air flows into a mixer. Fuel is injected by a fuel nozzle to mix with the pressurized air thereby forming a fuel-air mixture that is provided to the combustion chamber for combustion. Ignition of the fuel-air mixture is accomplished by one or more igniters, and the resulting combustion gases flow along the axial direction A toward, and into, a first stage turbine nozzle of the HP turbine 32. The first stage turbine nozzle is defined by an annular flow channel that includes a plurality of radially extending, circumferentially spaced nozzle vanes that turn the combustion gases so that they flow angularly and impinge upon first stage turbine blades of the HP turbine 32. The combustion gases exit the HP turbine 32, flow through the LP turbine 34, and exit the core duct 42 through the core exhaust nozzle 40 to produce a core air stream, also referred to as a second thrust stream S2. As noted above, the HP turbine 32 drives the HP compressor 28 via the HP shaft 36, and the LP turbine 34 drives the LP compressor 26, the primary fan 52, and the mid-fan 90 via the LP shaft 38.

[0035] The other portion of the second airflow flowing downstream of the mid-fan 90 is flows into the fan duct 72. The air enters the fan duct 72 through the fan duct inlet 76. The air flows generally along the axial direction A through the fan duct 72 and is ultimately exhausted from the fan duct 72 through the fan exhaust nozzle 78 to produce a third stream, also referred to as a third thrust stream S3.

[0036] The third thrust stream S3 means a secondary air stream that increases fluid energy to produce a minority of total propulsion system thrust. In some embodiments, a pressure ratio of the third stream is higher than that of the primary propulsion stream (e.g., a bypass or a propeller driven propulsion stream). The thrust may be produced through a dedicated nozzle or through mixing of the secondary air stream with the primary propulsion stream or a core air stream, e.g., into a common nozzle. In certain embodiments, an operating temperature of the secondary air stream is less than a maximum compressor discharge temperature for the engine. Furthermore, in certain embodiments, aspects of the third stream (e.g., airstream properties, mixing properties, or exhaust properties), and, thereby, a percent contribution to total thrust, are passively adjusted during engine operation or can be modified purposefully through the use of engine control features (such as fuel flow, electric machine power, variable stators, variable inlet guide vanes, valves, variable exhaust geometry, or fluidic features) to adjust or to improve overall system performance across a broad range of potential operating conditions.

[0037] The turbine engine 10 depicted in FIG. 1 is by way of example only. In other embodiments, the turbine engine 10 may have any other suitable configuration. For example, in other embodiments, the primary fan 52 may be configured in any other suitable manner (e.g., as a fixed pitch fan) and further may be supported using any other suitable fan frame configuration. In other embodiments, the primary fan 52 can be ducted by a fan casing or a nacelle such that a bypass passage is defined between the fan casing and the fan cowl 70. Moreover, in other embodiments, any other suitable number or configuration of compressors, turbines, shafts, or a combination thereof may be provided. In still other embodiments, aspects of the present disclosure may be incorporated into any other suitable turbine engine, such as, for example, turbofan engines, propfan engines, turbojet engines, turboprop, turboshaft engines, and / or turbine engines defining two streams (e.g., a bypass stream and a core air stream).

[0038] FIG. 2 is a schematic, cross-sectional side view of a gearbox assembly 200 for the turbine engine 10 (FIG. 1 ), taken along a longitudinal centerline axis 12 of the turbine engine 10, according to the present disclosure. The gearbox assembly 200 can be utilized as the gearbox assembly 55 of FIG. 1. The gearbox assembly 200 includes an epicyclic gear assembly 202 in a compound symmetrical arrangement. The epicyclic gear assembly 202 includes a sun gear 204, a plurality of planet gears 206 (only one of which is visible in FIG. 2), and a ring gear 208. For clarity, only a portion of the gears is shown. The plurality of planet gears 206 are contained and supported by a planet carrier 210 (shown schematically in FIG 2). The gearbox assembly 200 is a star type configuration or a rotating ring gear type gearbox assembly (e.g., the ring gear 208 is rotating and the planet carrier 210 is fixed and stationary). In such an arrangement, the primary fan 52 (FIG. 1 ) is driven by the ring gear 208. In this way, the ring gear 208 is an output of the gearbox assembly 200. However, other suitable types of gearbox assemblies may be employed. In one non-limiting embodiment, the gearbox assembly 200 may be a planetary configuration, in which the ring gear 208 is held fixed, with the planet carrier 210 allowed to rotate. In such an arrangement, the primary fan 52 (FIG. 1) is driven by the planet carrier 210. In this way, the plurality of planet gears 206 are the output of the gearbox assembly 200.

[0039] An input shaft 212 is coupled to the sun gear 204. The input shaft 212 is coupled to the turbine section (FIG. 1 ). For example, the input shaft 212 can be coupled to, or can embody, the LP shaft 38 (FIG. 1 ). Radially outward of the sun gear 204, and intermeshing therewith, is the plurality of planet gears 206 that are coupled together and supported by the planet carrier 210. The planet carrier 210 supports and constrains the plurality of planet gears 206 such that the plurality of planet gears 206 do not together rotate around the sun gear 204 while enabling each planet gear 206 of the plurality of planet gears 206 to rotate about a longitudinal centerline axis 213 of each planet gear 206. For example, the planet carrier 210 iscoupled to a static structure (removed from the view of FIG. 2 for clarity) of the turbine engine 10 (FIG. 1 ), as detailed further below. Radially outwardly of the plurality of planet gears 206, and intermeshing therewith, is the ring gear 208, which is an annular ring gear. FIG 2 shows the ring gear 208 is formed of two separate components that are coupled together. In some embodiments, the ring gear 208 may be a single unitary component. The ring gear 208 is coupled via an output shaft 214 to the primary fan 52 (FIG. 1 ) and rotates to drive rotation of the primary fan 52 (FIG. 1) about the longitudinal centerline axis 12. For example, the output shaft 214 is coupled to the fan shaft 56 (FIG. 1). In some embodiments, the output shaft 214 and the fan shaft 56 (FIG. 1) are formed as a single integral component.

[0040] Each of the plurality of planet gears 206 is a compound gear that includes a first stage planet gear 216 and a second stage planet gear 218 coupled together. The first stage planet gear 216 includes a greater diameter than a diameter of the second stage planet gear 218. Each of the sun gear 204, the plurality of planet gears 206, and the ring gear 208 comprises teeth about their periphery to intermesh with the other gears. For example, each of the sun gear 204, the plurality of planet gears 206, and the ring gear 208 is a double helical gear with first and second sets of helical teeth that are all inclined at the same acute angle relative to a planet gear axis. In particular, the sun gear 204 comprises a first set of sun gear teeth 220 and a second set of sun gear teeth 222. Each of the first stage planet gears 216 includes a first set of planet gear teeth 224 and a second set of planet gear teeth 226, and each of the second stage planet gears 218 includes a third set of planet gear teeth 228 and a fourth set of planet gear teeth 230. The ring gear 208 includes a first set of ring gear teeth 232 and a second set of ring gear teeth 234. The sun gear 204, the plurality of planet gears 206, and the ring gear 208 may include any type of gear, such as, for example, spur gears (e.g., gear teeth that are straight cut and are not set at anangle relative to the planet gear axis), helical gears (e.g., gear teeth that are positioned at an acute angle relative to the planet gear axis), or the like.

[0041] The first set of planet gear teeth 224 and the second set of planet gear teeth 226 of the first stage planet gear 216 mesh with the first set of sun gear teeth 220 and the second set of sun gear teeth 222 of the sun gear 204, respectively. The third set of planet gear teeth 228 of the second stage planet gear 218 meshes with the first set of ring gear teeth 232 of the ring gear 208. The fourth set of planet gear teeth 230 of the second stage planet gear 218 meshes with the second set of ring gear teeth 234 of the ring gear 208.

[0042] Each of the planet gears 206 of the plurality of planet gears 206 includes an integral pin 240 about which a respective planet gear 206 rotates. The integral pin 240 is coupled to the planet carrier 210 and is disposed within a bore 242 of a respective planet gear 206. The planet gear 206 rotates with respect to the integral pin 240. The second stage planet gear 218 is supported by one or more roller bearings 244 that are disposed within the bore 242. FIG. 2 shows the one or more roller bearings 244 include two roller bearings 244 including a first roller bearing 244a and a second roller bearing 244b. A respective planet gear 206, however, can include any number of roller bearings 244, as desired. The second roller bearing 244b is located aft of the first roller bearing 244a. In this way, the first roller bearing 244a is referred to as a forward roller bearing and the second roller bearing 244b is referred to as an aft roller bearing. An axial distance between the first roller bearing 244a and the second roller bearing 244b is selected to balance forces on the integral pin 240 by the one or more roller bearings 244. For example, the axial distance is selected such that there is minimal (e.g., about zero) delta deflection in the radial direction between the first roller bearing 244a and the second roller bearing 244b. In this way, the first roller bearing 244a and the second roller bearing 244bradially deflect substantially equally during operation. The roller bearings 244 allow rotation of the planet gear 206 with respect to the integral pin 240.

[0043] The one or more roller bearings 244 include an outer race 246 and an inner race248. The outer race 246 is defined by a radially inner surface of the second stage planet gear 218. The inner race 248 is defined by the integral pin 240. In this way, the integral pin 240 is referred to as an integral pin such thatthe inner race 248 of the one or more roller bearings 244 is integral with the integral pin 240, and the inner race 248 and the integral pin 240 form a single, unitary component, as detailed further below. The one or more roller bearings 244 include a plurality of rolling elements 245 disposed between the outer race 246 and the inner race 248. FIG. 2 shows four such rolling elements 245, but the one or more roller bearings 244 may each include any number of rolling elements 245. The plurality of rolling elements 245 allows rotation of the planet gear 206 with respect to the integral pin 240. The plurality of rolling elements 245 includes generally cylindrical rolling elements.

[0044] The gearbox assembly 200 includes a gear ratio that defines a ratio of the speed of the input gear (e.g., the sun gear 204) to the speed of the output (e.g., the ring gear 208) through the gearbox assembly 200. Embodiments of the present disclosure detailed herein provide for increased gear ratios for a fixed gear envelope (e.g., with the same size ring gear), or alternatively, a smaller diameter ring gear may be used to achieve the same gear ratios. A total gear ratio of the planet gear 206 includes a first gear ratio of the first stage planet gear 216 and a second gear ratio of the second stage planet gear 218. The first gear ratio of the first stage planet gear 216 is less than the second gear ratio of the second stage planet gear 218. In some embodiments, the first gear ratio of the first stage planet gear 216 is greater than or equal to the second gear ratio of the second stage planet gear 218. In this way, a split of the total gear ratio between the first gear ratio and the second gear ratio can be selected for a particular applicationas desired. The total gear ratio of the planet gear 206 is in a range of six to one (6:1) and twelve to one (12:1). The total gear ratio is selected based on engine size and power requirements, and a selection of components for a particular gearbox assembly 200. For example, the total gear ratio is based on the speed of the primary fan 52 (e.g., the tip speed of the primary fan 52 of FIG. 1) and the speed of the LP turbine 34 (e.g., based on the number of stages of the LP turbine 34 of FIG. 1).

[0045] FIG. 3 is detailed schematic, cross-sectional view of the gearbox assembly 200 illustrating details of the integral pin 240, taken at detail 249 in FIG. 2, according to the present disclosure. The ring gear 208 (FIG. 2), the input shaft 212 (FIG 2), the output shaft 214 (FIG. 2), and the planet gear teeth 228, 230 (FIG. 2) are removed from FIG. 3 for clarity. The planet carrier 210 includes a forward wall 215 and an aft wall 217. The forward wall 215 and the aft wall 217 are generally annular about the longitudinal centerline axis 12 (FIG. 2). The forward wall 215 includes a forward pin aperture 219 extending therethrough, and the aft wall 217 includes an aft pin aperture 221 extending therethrough. The planet carrier 210 is coupled to a static structure 223 of the turbine engine 10 (FIG. 1) by one or more planet carrier fastening mechanisms 225. In this way, the gearbox assembly 200 is a star configuration, and the planet carrier 210, and, thus, the plurality of planet gears 206 do not rotate about the longitudinal centerline axis 12 (FIG 2). The one or more planet carrier fastening mechanisms 225 are bolts in FIG. 3, but the one or more planet carrier fastening mechanisms 225 can include any type of fastening mechanisms, such as, for example, screws, rivets, or the like. In some embodiments, the gearbox assembly 200 is a planetary configuration, and the planet carrier 210 is coupled to the output shaft 214 such that the planet carrier 210, and, thus, the plurality of planet gears 206 rotate about the longitudinal centerline axis 12 (FIG. 2).

[0046] The integral pin 240 includes a body 250 having an outer surface 252 and an inner surface 254. The integral pin 240 is a hollow pin such that the integral pin 240 includes a hollow interior 255 therein. The body 250 includes a forward coupling portion 256, an aft coupling portion 258, and a middle portion 260 that extends between the forward coupling portion 256 and the aft coupling portion 258. The body 250 is a generally cylindrical body suchthatthe integral pin 240 is generically cylindrical. The forward coupling portion 256 couples the integral pin 240 within the forward wall 215 of the planet carrier 210, and the aft coupling portion 258 couples the integral pin 240 within the aft wall 217 of the planet carrier 210.

[0047] The forward coupling portion 256 includes one or more stiffness reduction features 257 to avoid a contact pressure at edges of the press fit between the forward coupling portion 256 and the forward wall 215. For example, an increased stress concentration at the edges of the press fit results when bending of the integral pin 240 occurs if the integral pin 240 is overly stiff at the coupling between the integral pin 240 and the planet carrier 210. In this way, the one or more stiffness reduction features 257 help to avoid such a stress concentration at the edge of the press fit. The one or more stiffness reduction features 257 also help to tune the stiffness of the body 250 of the integral pin 240 to provide for a substantially symmetrical deflection between the first roller bearing 244a and the second roller bearing 244b. In this way, the one or more stiffness reduction features 257 are tuned such that a contact stress of the first roller bearing 244a and a contact stress of the second roller bearing 244b is substantially equal.

[0048] The one or more stiffness reduction features 257 include a channel disposed within the forward coupling portion 256. The geometry of the one or more stiffness reduction features 257 can include an asymmetrical cross-sectional profile. In this way, the geometry of the one or more stiffness reduction features 257 helps to alleviate the contact pressure developed at the press fit by permitting the distribution of the loading developed therein to a greater portionof the forward coupling portion 256. This distribution may be attributable to an increase in the flexibility of the forward coupling portion 256 resulting from the asymmetrical cross-sectional geometry of the one or more stiffness reduction features 257. The cross-sectional profile of the one or more stiffness reduction features 257 may lack a radial symmetry and / or anaxial symmetry. In some embodiments, however, the cross-sectional profile of the one or more stiffness reduction features 257 is symmetrical. The one or more stiffness reduction features 257 include a first stiffness reduction feature 257a on a forward side of the forward coupling portion 256, and a second stiffness reduction feature 257b on an aft side of the forward coupling portion 256. The one or more stiffness reduction features 257 can include any number of stiffness reduction features 257 as desired.

[0049] The integral pin 240 is coupled within the planet carrier 210 by a press fit between the forward coupling portion 256 and the forward wall 215, and by a press fit between the aft coupling portion 258 and the aft wall 217. The integral pin 240 also includes a pin retention portion 262 that extends axially from the aft coupling portion 258. A pin fastening mechanism 264 is coupled to the pin retention portion 262, for example, by a threaded connection, to secure the integral pin 240 within the planet carrier 210. The pin retention portion 262 includes one or more anti-rotation slots 265 that interface with the pin fastening mechanism 264 to clamp the integral pin 240 on the planet carrier 210. The pin fastening mechanism 264 includes a nut, such as, for example, a locknut, or the like. The integral pin 240 also includes a clockingtab 266 atthe forward coupling portion 256 to help ensure that the integral pin 240 is positioned rotationally within the planet carrier 210. For example, the clocking tab 266 interfaces with the forward wall 215 to locate the integral pin 240 at a particular circumferential position within the planet carrier 210.

[0050] The integral pin 240 includes a varying outer diameter along an axial length of the integral pin 240. For example, the middle portion 260 includes a first pin diameter Di, the forward coupling portion 256 includes a second pin diameter D2, and the aft coupling portion 258 includes a third pin diameter D3. The first pin diameter Di, the second pin diameter D2, and the third pin diameter D3 are all outer diameters of the integral pin 240 and are measured from the outer surface 252 of the integral pin 240 and passing through the center of the integral pin 240. The integral pin 240 can also include a varying inner diameter along the axial length of the integral pin 240. The inner diameter is the measurement of between the inner surface 254 of the integral pin 240 and passing through the center of the integral pin 240. The second pin diameter D2is greater than the first pin diameter Di and is greater than the third pin diameter D3. The third pin diameter D3 is less than the first pin diameter Di and less than the second pin diameter D2. The pin diameters Di, D2, D3 allow the integral pin 240 to be inserted through the planet carrier 210 from the forward end of the planet carrier 210. The second pin diameter D2is greater than a diameter of the forward pin aperture 219, and the third pin diameter D3 is greater than a diameter of the aft pin aperture 221 such that the forward coupling portion 256 is press fit into the forward pin aperture 219 and the aft coupling portion 258 is press fit into the aft pin aperture 221. The second pin diameter D2is also greater (only slightly greater in FIG. 3) than a diameter of the outer race 246 such that one or more roller bearings 244 can pass through the second pin diameter D2during assembly, and the forward coupling portion 256 is prevented from passing axially beyond the outer race 246 of the first roller bearing 244a. The difference between the first diameter Di and the diameter of the outer race 246 is made to reduce the size of the planet gear 206 and of the planet carrier 210. The third pin diameter D3 is less than a diameter of the inner race 248 to provide a balance of forces when the pin fastening mechanism 264 is coupled to the pin retention portion 262.

[0051] The integral pin 240 also includes one or more bearing cage assemblies 270. The one or more bearing cage assemblies 270 retain the plurality of rolling elements 245 within the one or more roller bearings 244. The one or more bearing cage assemblies 270 are positioned on the middle portion 260. Each bearing cage assembly 270 includes one or more pin shoulders 272 that extend radially outward from the outer surface 252 of the integral pin 240. The one or more pin shoulders 272 include a pair of pin shoulders 272 that are spaced axially from each other and define a roller element channel 274 in which the plurality of rolling elements 245 are disposed. The roller element channel 274 includes the inner race 248. In this way, the plurality of rolling elements 245 are constrained within the one or more bearing cage assemblies 270 by the outer race 246, the inner race 248, and the one or more pin shoulders 272. For example, the outer race 246 and the inner race 248 constrain and secure the plurality of rolling elements 245 radially, and the one or more pin shoulders 272 constrain and secure the plurality of rolling elements 245 axially.

[0052] The one or more bearing cage assemblies 270 also include one or more bearing cages 276 that restrain each individual rolling element 245 of the plurality of rolling elements 245. For example, the one or more bearing cages 276 each includes one or more slots that receive a respective rolling element 245. In this way, the one or more bearing cages 276 restrain the plurality of rolling elements 245 axially and circumferentially to maintain circumferential spacing between the plurality of rolling elements 245. The one or more bearing cages 276 are mounted on, and are coupled to, the one or more pin shoulders 272. The plurality of rolling elements 245 are disposed within the one or more bearing cages 276 such that the plurality of rolling elements 245 allow the planet gear 206 to rotate about the longitudinal centerline axis 12 (FIG. 2).

[0053] The integral pin 240 includes one or more lubricant holes 278 extending through the integral pin 240 from the inner surface 254 to the outer surface 252. In particular, the one or more lubricant holes 278 extend through the one or more pin shoulders 272. The one or more lubricant holes 278 include discrete holes and are located at particular circumferential locations about the integral pin 240, as desired. In this way, lubricant (e.g., oil) is provided to each of the one or more roller bearings 244 through the one or more lubricant holes 278 to lubricate the plurality of rolling elements 245 of each roller bearing 244, as detailed further below.

[0054] A lubricant sleeve 280 is inserted into, and disposed within, the hollow interior 255 of the integral pin 240. The lubricant sleeve 280 is sized such that the lubricant sleeve 280 is spaced from the inner surface 254 of the integral pin 240 when the lubricant sleeve 280 is disposed within the hollow interior 255. In this way, a lubricant cavity 282 is defined between the inner surface 254 of the integral pin 240 and the lubricant sleeve 280. Lubricant is supplied to the lubricant cavity 282, as detailed further below. The lubricant sleeve 280 includes a lubricant passage 284 that defines a lubricant flowpath 286 therein. The lubricant passage 284 is disposed within the lubricant sleeve 280 and extends axially and radially through the lubricant sleeve 280. The lubricant passage 284 is in fluid communication with a lubricant supply (not shown in the view of FIG. 3) for receiving lubricant therein within the lubricant flowpath 286. The lubricant sleeve 280 includes one or more seals 288 for sealing the lubricant cavity 282 such that lubricant in the lubricant cavity 282 is prevented by the one or more seals 288 from leaking out of the lubricant cavity 282. For example, the one or more seals 288 can include a seal 288 located about the forward end of the lubricant sleeve 280 and a seal 288 located about the aft end of the lubricant sleeve 280. The one or more seals 288 include one or more O-rings, but can include any type of seals for sealing the lubricant cavity 282. The lubricant sleeve 280 is coupled to the integral pin 240 by a lubricant sleeve fastening mechanism 290. In theembodiment of FIG. 3, the lubricant sleeve fastening mechanism 290 is a threaded nut that is secured against the lubricant sleeve 280 to secure the lubricant sleeve 280 within the integral pin240.

[0055] In operation, the lubricant is supplied from the lubricant supply through the lubricant flowpath 286 within the lubricant passage 284 as indicated by the arrows 287. The lubricant flows from the lubricant flowpath 286 into the lubricant cavity 282 between the lubricant sleeve 280 and the inner surface 254 of the integral pin 240. The lubricant then flows through the lubricant holes 278 and is supplied to the one or more roller bearings 244 to lubricate the plurality of rolling elements 245.

[0056] FIG. 4 is an enlarged schematic, cross-sectional view of a portion of an integral pin 440 for a gearbox assembly, taken along a longitudinal centerline axis of the integral pin 440, according to another embodiment. FIG. 4 shows only a forward portion of the integral pin 440. The integral pin 440 is substantially similar to the integral pin 240 of the aspects shown in FIGS. 2 and 3 and includes many of the same or similar components detailed above. The integral pin 440 includes a body 450, a forward coupling portion 456, an inner race 448, and one or more lubricant holes 478. Other components of the integral pin 440 are the same as or similar to the components of the integral pin 240 of FIGS. 2 and 3, but are not labeled or shown for clarity.

[0057] A lubricant sleeve 480 is disposed within the integral pin 440. The lubricant sleeve 480 is retained and is secured within the integral pin 440 by a fastening mechanism 490. The fastening mechanism 490 is different than the lubricant sleeve fastening mechanism 290 in FIG. 3. For example, the fastening mechanism 490 is a retaining ring. The retaining ring is an annular clip, also referred to as a circlip, and is made of an elastic material. The fastening mechanism 490 includes a ring with open ends that are snapped into place about the lubricant sleeve 480 to secure the lubricant sleeve 480 within the integral pin 440. The fasteningmechanism 490 permits rotation of the lubricant sleeve 480, but prevents the lubricant sleeve 480 from moving axially. The fastening mechanism 490 is disposed within a fastening mechanism cavity 491 within the integral pin 440.

[0058] The integral pins 240, 440 detailed herein provide for an integral pin and roller bearing. For example, the integral pins 240, 440 provide the pin and the roller bearing inner race and the bearing cages within a single component. In this way, the integral pins 240, 440 of the present disclosure provide for a reduction in parts, thereby, enabling a smaller gearbox assembly as compared to gearbox assemblies without the benefit of the present disclosure. Accordingly, the present disclosure provides for an improved integral pin 240, 440 that allows for reducing a weight of the gearbox assembly, and, thus, reducing a weight of the turbine engine, as compared to gearbox assemblies without the benefit of the present disclosure. The integral pins 240, 440 detailed herein enable an axially compact two-stage compound symmetric gearbox assembly with roller bearings, thereby enabling gearbox assemblies with greater gear ratios and higher torque outputs as compared to gearbox assemblies without the benefit of the present disclosure.

[0059] Further aspects are provided by the subject matter of the following clauses.

[0060] A gearbox assembly comprises a planet carrier, a planet gear disposed within the planet carrier, one or more roller bearings disposed within the planet gear, the one or more roller bearings including a plurality of rolling elements, and an integral pin disposed within the planet carrier and extending through the planet gear, the integral pin including one or more pin shoulders extending from the integral pin, and the plurality of rolling elements being disposed axially between the one or more pin shoulders and radially between the integral pin and the planet gear, the one or more pin shoulders axially constraining the plurality of rolling elements, the planet gear rotating about the one or more roller bearings with respect to the integral pin.

[0061] The gearbox assembly of the preceding clause, the one or more pin shoulders including a pair of pin shoulders, the plurality of rolling elements being axially constrained between the pair of pin shoulders.

[0062] The gearbox assembly of any preceding clause, the one or more roller bearings including two roller bearings spaced axially on the integral pin.

[0063] The gearbox assembly of any preceding clause, the integral pin being secured to the planet carrier by a pin fastening mechanism at an aft end of the integral pin.

[0064] The gearbox assembly of any preceding clause, the integral pin including an outer surface that defines an inner race of the one or more roller bearings such that the inner race is integral with the integral pin.

[0065] The gearbox assembly of any preceding clause, the planet gear defining an outer race of the one or more roller bearings.

[0066] The gearbox assembly of any preceding clause, the planet carrier including a forward wall and an aft wall, the integral pin including a forward coupling portion and an aft coupling portion, the forward coupling portion being coupled within the forward wall, and the aft coupling portion being coupled within the aft wall.

[0067] The gearbox assembly of any preceding clause, the forward coupling portion being press fit into the forward wall, and the aft coupling portion is press fit into the aft wall.

[0068] The gearbox assembly of any preceding clause, the forward wall including a forward pin aperture and the aft wall includes an aft pin aperture, the forward coupling portion being disposed within forward pin aperture, and the aft coupling portion being disposed within the aft pin aperture.

[0069] The gearbox assembly of any preceding clause, the forward pin aperture including a diameter that is greater than a diameter of an outer race of the one or more roller bearings.

[0070] The gearbox assembly of any preceding clause, the integral pin including a middle portion extending between the forward coupling portion and the aft coupling portion, the one or more roller bearings being disposed on the middle portion.

[0071] The gearbox assembly of any preceding clause, the middle portion including a first pin diameter, the forward coupling portion includes a second pin diameter, and the aft coupling portion includes a third pin diameter, the first pin diameter, the second pin diameter, and the third pin diameter being different.

[0072] The gearbox assembly of any preceding clause, further including one or more lubricant holes extending through the integral pin, lubricant being supplied to the one or more roller bearings through the one or more lubricant holes.

[0073] The gearbox assembly of any preceding clause, further including a lubricant sleeve disposed within the integral pin, the lubricant being supplied to the one or more roller bearings from the lubricant sleeve.

[0074] The gearbox assembly of any preceding clause, the lubricant sleeve being secured to the integral pin by a lubricant sleeve fastening mechanism. The gearbox assembly of any preceding clause, further comprising an epicyclic gear assembly including a sun gear, a ring gear, and the planet gear, the planet gear meshing with the sun gear and the ring gear.

[0075] The gearbox assembly of any preceding clause, the epicyclic gear assembly being a star configuration.

[0076] The gearbox assembly of any preceding clause, the epicyclic gear assembly being a planetary configuration.

[0077] The gearbox assembly of any preceding clause, further comprising an input shaft coupled to a turbine section of a turbine engine, and an output shaft coupled to a fan of the turbine engine.

[0078] The gearbox assembly of any preceding clause, the planet gear being a compound planet gear including a first stage planet gear and a second stage planet gear.

[0079] The gearbox assembly of any preceding clause, the first stage planet gear including a diameter greater than a diameter of the second stage planet gear.

[0080] The gearbox assembly of any preceding clause, the integral pin being disposed within a bore of the planet gear.

[0081] The gearbox assembly of any preceding clause, the one or more roller bearings including a first roller bearing and a second roller bearing.

[0082] The gearbox assembly of any preceding clause, an axial distance between the first roller bearing and the second roller bearing being defined between the first roller bearing and the second roller bearing such that there is zero delta deflection between the firstroller bearing and the second roller bearing.

[0083] The gearbox assembly of any preceding clause, the outer race being defined by a radially inner surface of the second stage planet gear.

[0084] The gearbox assembly of any preceding clause, the inner race and the integral pin forming a single, unitary component.

[0085] The gearbox assembly of any preceding clause, the plurality of rolling elements being generally cylindrical rolling elements.

[0086] The gearbox assembly of any preceding clause, the planet carrier being coupled to a static structure of a turbine engine by one or more planet carrier fastening mechanisms.

[0087] The gearbox assembly of any preceding clause, the integral pin including a body having an outer surface, an inner surface, and a hollow interior.

[0088] The gearbox assembly of any preceding clause, the forward coupling portion including one or more stiffness reduction features to reduce an edge contact pressure within the press fit between the forward coupling portion and the forward wall.

[0089] The gearbox assembly of any preceding clause, the one or more stiffness reduction features including a channel disposed within the forward coupling portion.

[0090] The gearbox assembly of any preceding clause, the one or more stiffness reduction features including an asymmetrical cross-sectional profile.

[0091] The gearbox assembly of any preceding clause, the one or more stiffness reduction features including a first stiffness reduction feature on a forward end of the forward coupling portion, and a second stiffness reduction feature on an aft end of the forward coupling portion.

[0092] The gearbox assembly of any preceding clause, the integral pin including a pin retention portion extending axially from the aft coupling portion, the pin fastening mechanism being coupled to the pin retention portion.

[0093] The gearbox assembly of any preceding clause, the pin fastening mechanism being a nut.

[0094] The gearbox assembly of any preceding clause, the pin retention portion including one or more anti-rotation slots that prevent the integral pin from rotating with respect to the planet carrier.

[0095] The gearbox assembly of any preceding clause, the integral pin further including a clocking tab for positioning the integral circumferentially within the planet carrier.

[0096] The gearbox assembly of any preceding clause, the clocking tab extending axially from the forward coupling portion and interfacing with the forward wall of the planet carrier.

[0097] The gearbox assembly of any preceding clause, the integral pin including a varying outer diameter along an axial length of the integral pin.

[0098] The gearbox assembly of any preceding clause, the second pin diameter being greater than the first pin diameter.

[0099] The gearbox assembly of any preceding clause, the third pin diameter being less than the first pin diameter.

[0100] The gearbox assembly of any preceding clause, the second pin diameter being greater than a diameter of the outer race.

[0101] The gearbox assembly of any preceding clause, the first pin diameter, the second pin diameter, and the third pin diameter being outer diameters of the integral pin.

[0102] The gearbox assembly of any preceding clause, the integral pin including one or more bearing cage assemblies that constrain the plurality of rolling elements.

[0103] The gearbox assembly of any preceding clause, each bearing cage assembly comprising the one or more pin shoulders, the inner race, and the outer race.

[0104] The gearbox assembly of any preceding clause, the plurality of rolling elements being constrained within the one or more bearing cage assemblies by the outer race, the inner race, and the one or more pin shoulders.

[0105] The gearbox assembly of any preceding clause, the one or more bearing cage assemblies constraining the plurality of rolling elements radially and axially.

[0106] The gearbox assembly of any preceding clause, the one or more bearing cage assemblies further including one or more bearing cages that restrain each individual rolling element of the plurality of rolling elements.

[0107] The gearbox assembly of any preceding clause, the one or more lubricant holes extending through the one or more shoulders.

[0108] The gearbox assembly of any preceding clause, the one or more lubricant holes being discrete holes.

[0109] The gearbox assembly of any preceding clause, further including a lubricant cavity defined between the lubricant sleeve and the integral pin.

[0110] The gearbox assembly of any preceding clause, the lubricant sleeve including a lubricant passage defining a lubricant flowpath therein, lubricant being supplied to the lubricant cavity through the lubricant flowpath.

[0111] The gearbox assembly of any preceding clause, the lubricant sleeve including one or more seals for sealing the lubricant cavity.

[0112] The gearbox assembly of any preceding clause, the one or more seals including O-rings.

[0113] The gearbox assembly of any preceding clause, the lubricant sleeve fastening mechanism including a threaded nut.

[0114] The gearbox assembly of any preceding clause, the lubricant sleeve fastening mechanism including a retaining ring that secures the lubricant sleeve axially within the integral pin.

[0115] The gearbox assembly of any preceding clause, a power rating of the engine being greater than 7 megawatts, greater than 15 megawatts, or greater than 22 megawatts.

[0116] The gearbox assembly of any preceding clause, the engine being an unducted single fan engine.

[0117] The gearbox assembly of any preceding clause, a gear ratio of the gearbox assembly being between 6:1 to 12:1.

[0118] A turbine engine comprises a low-pressure shaft coupled to a turbine section, a fan shaft coupled to a fan, and a gearbox assembly, the low-pressure shaft transferring torque tothe fan shaft through the gearbox assembly, the gearbox assembly comprising a planet carrier, a planet gear disposed within the planet carrier, one or more roller bearings disposed within the planet gear, the one or more roller bearings including a plurality of rolling elements, and an integral pin disposed within the planet carrier and extending through the planet gear, the integral pin including one or more pin shoulders extending from the integral pin, and the plurality of rolling elements being disposed axially between the one or more pin shoulders and radially between the integral pin and the planet gear, the one or more pin shoulders axially constraining the plurality of rolling elements, the planet gear rotating about the one or more roller bearings with respect to the integral pin.

[0119] The turbine engine of the preceding clause, the one or more pin shoulders including a pair of pin shoulders, the plurality of rolling elements being axially constrained between the pair of pin shoulders.

[0120] The turbine engine of any preceding clause, the one or more roller bearings including two roller bearings spaced axially on the integral pin.

[0121] The turbine engine of any preceding clause, the integral pin being secured to the planet carrier by a pin fastening mechanism at an aft end of the integral pin.

[0122] The turbine engine of any preceding clause, the integral pin including an outer surface that defines an inner race of the one or more roller bearings such that the inner race is integral with the integral pin. The gearbox assembly of any preceding clause, further comprising a plurality of planet gears, each planet gear including an integral pin.

[0124] The turbine engine of any preceding clause, the planet gear defining an outer race of the one or more roller bearings.

[0125] The turbine engine of any preceding clause, the planet carrier including a forward wall and an aft wall, the pin including a forward coupling portion and an aft coupling portion, !heforward coupling portion being coupled within the forward wall, and the aft coupling portion being coupled within the aft wall.

[0126] The turbine engine of any preceding clause, the forward coupling portion being press fit into the forward wall, and the aft coupling portion is press fit into the aft wall.

[0127] The turbine engine of any preceding clause, the forward wall including a forward pin aperture and the aft wall includes an aft pin aperture, the forward coupling portion being disposed within forward pin aperture, and the aft coupling portion being disposed within the aft pin aperture.

[0128] The turbine engine of any preceding clause, the forward pin aperture including a diameter that is greater than a diameter of an outer race of the one or more roller bearings.

[0129] The turbine engine of any preceding clause, the integral pin including a middle portion extending between the forward coupling portion and the aft coupling portion, the one or more roller bearings being disposed on the middle portion.

[0130] The turbine engine of any preceding clause, the middle portion including a first pin diameter, the forward coupling portion includes a second pin diameter, and the aft coupling portion includes a third pin diameter, the first pin diameter, the second pin diameter, and the third pin diameter being different.

[0131] The turbine engine of any preceding clause, further including one or more lubricant holes extending through the integral pin, lubricant being supplied to the one or more roller bearings through the one or more lubricant holes.

[0132] The turbine engine of any preceding clause, further including a lubricant sleeve disposed within the integral pin, the lubricant being supplied to the one or more roller bearings from the lubricant sleeve.

[0133] The turbine engine of any preceding clause, the lubricant sleeve being secured to the integral pin by a lubricant sleeve fastening mechanism.

[0134] The turbine engine of any preceding clause, further comprising a plurality of planet gears, each planet gear including an integral pin.

[0135] The turbine engine of any preceding clause, further comprising an epicyclic gear assembly including a sun gear, a ring gear, and the planet gear, the planet gear meshing with the sun gear and the ring gear.

[0136] The turbine engine of any preceding clause, of any preceding clause, the epicyclic gear assembly being a star configuration.

[0137] The turbine engine of any preceding clause, the epicyclic gear assembly being a planetary configuration.

[0138] The turbine engine of any preceding clause, further comprising an input shaft coupled to a turbine section of a turbine engine, and an output shaft coupled to a fan of the turbine engine.

[0139] The turbine engine of any preceding clause, the planet gear being a compound planet gear including a first stage planet gear and a second stage planet gear.

[0140] The turbine engine of any preceding clause, the first stage planet gear including a diameter greater than a diameter of the second stage planet gear.

[0141] The turbine engine of any preceding clause, the integral pin being disposed within a bore of the planet gear.

[0142] The turbine engine of any preceding clause, the one or more roller bearings including a first roller bearing and a second roller bearing.

[0143] The turbine engine of any preceding clause, an axial distance between the first roller bearing and the second roller bearing being defined between the first roller bearing and thesecond roller bearing such that there is zero delta deflection between the firstroller bearing and the second roller bearing.

[0144] The turbine engine of any preceding clause, the outer race being defined by a radially inner surface of the second stage planet gear.

[0145] The turbine engine of any preceding clause, the inner race and the integral pin forming a single, unitary component.

[0146] The turbine engine of any preceding clause, the plurality of rolling elements being generally cylindrical rolling elements.

[0147] The turbine engine of any preceding clause, the planet carrier being coupled to a static structure of a turbine engine by one or more planet carrier fastening mechanisms.

[0148] The turbine engine of any preceding clause, the integral pin includes a body having an outer surface, an inner surface, and a hollow interior.

[0149] The turbine engine of any preceding clause, the forward coupling portion including one or more stiffness reduction features to reduce an edge contact pressure within the press fit between the forward coupling portion and the forward wall.

[0150] The turbine engine of any preceding clause, the one or more stiffness reduction features including a channel disposed within the forward coupling portion.

[0151] The turbine engine of any preceding clause, the one or more stiffness reduction features including an asymmetrical cross-sectional profile.

[0152] The turbine engine of any preceding clause, the one or more stiffness reduction features including a first stiffness reduction feature on a forward end of the forward coupling portion, and a second stiffness reduction feature on an aft end of the forward coupling portion.

[0153] The turbine engine of any preceding clause, the integral pin including a pin retention portion extending axially from the aft coupling portion, the pin fastening mechanism being coupled to the pin retention portion.

[0154] The turbine engine of any preceding clause, the pin fastening mechanism being a nut.

[0155] The turbine engine of any preceding clause, the pin retention portion including one or more anti-rotation slots that prevent the integral pin from rotating with respect to the planet carrier.

[0156] The turbine engine of any preceding clause, the integral pin further including a clocking tab for positioning the integral circumferentially within the planet carrier.

[0157] The turbine engine of any preceding clause, the clocking tab extending axially from the forward coupling portion and interfacing with the forward wall of the planet carrier.

[0158] The turbine engine of any preceding clause, the integral pin including a varying outer diameter along an axial length of the integral pin.

[0159] The turbine engine of any preceding clause, the second pin diameter being greater than the first pin diameter.

[0160] The turbine engine of any preceding clause, the third pin diameter being less than the first pin diameter.

[0161] The turbine engine of any preceding clause, the second pin diameter being greater than a diameter of the outer race.

[0162] The turbine engine of any preceding clause, the first pin diameter, the second pin diameter, and the third pin diameter being outer diameters of the integral pin.

[0163] The turbine engine of any preceding clause, the integral pin including one or more bearing cage assemblies that constrain the plurality of rolling elements.

[0164] The turbine engine of any preceding clause, each bearing cage assembly comprising the one or more pin shoulders, the inner race, and the outer race.

[0165] The turbine engine of any preceding clause, the plurality of rolling elements being constrained within the one or more bearing cage assemblies by the outer race, the inner race, and the one or more pin shoulders.

[0166] The turbine engine of any preceding clause, the one or more bearing cage assemblies constraining the plurality of rolling elements radially and axially.

[0167] The turbine engine of any preceding clause, the one or more bearing cage assemblies further including one or more bearing cages that restrain each individual rolling element of the plurality of rolling elements.

[0168] The turbine engine of any preceding clause, the one or more lubricant holes extending through the one or more shoulders.

[0169] The turbine engine of any preceding clause, the one or more lubricant holes being discrete holes.

[0170] The turbine engine of any preceding clause, further including a lubricant cavity defined between the lubricant sleeve and the integral pin.

[0171] The turbine engine of any preceding clause, the lubricant sleeve including a lubricant passage defining a lubricant flowpath therein, lubricant being supplied to the lubricant cavity through the lubricant flowpath.

[0172] The turbine engine of any preceding clause, the lubricant sleeve including one or more seals for sealing the lubricant cavity.

[0173] The turbine engine of any preceding clause, the one or more seals including O- nngs.

[0174] The turbine engine of any preceding clause, the lubricant sleeve fastening mechanism including a threaded nut.

[0175] The turbine engine of any preceding clause, the lubricant sleeve fastening mechanism including a retaining ring that secures the lubricant sleeve axially within the integral pin.

[0176] The turbine engine of any preceding clause, a power rating of the turbine engine being greater than 7 megawatts, greater than 15 megawatts, or greater than 22 megawatts.

[0177] The turbine engine of any preceding clause, the turbine engine being an unducted single fan engine.

[0178] The turbine engine of any preceding clause, a gear ratio of the gearbox assembly being between 6:1 to 12:1.

[0179] Although the foregoing description is directed to the preferred embodiments of the present disclosure, other variations and modifications will be apparent to those skilled in the art and may be made without departing from the spirit or the scope of the disclosure. Moreover, features described in connection with one embodiment of the present disclosure may be used in conjunction with other embodiments, even if not explicitly stated above.

Claims

CLAIMS1. A gearbox assembly comprising: a planet carrier; a planet gear disposed within the planet carrier; one or more roller bearings disposed within the planet gear, the one or more roller bearings including a plurality of rolling elements; and an integral pin disposed within the planet carrier and extending through the planet gear, the integral pin including one or more pin shoulders extending from the integral pin, and the plurality of rolling elements being disposed axially between the one or more pin shoulders and radially between the integral pin and the planet gear, the one or more pin shoulders axially constraining the plurality of rolling elements, wherein the planet gear rotates about the one or more roller bearings with respect to the integral pin.

2. The gearbox assembly of claim 1 , wherein the one or more pin shoulders include a pair of pin shoulders, the plurality of rolling elements being axially constrained between the pair of pin shoulders.

3. The gearbox assembly of claim 1 , wherein the one or more roller bearings include two roller bearings spaced axially on the integral pin.

4. The gearbox assembly of claim 1 , wherein the integral pin is secured to the planet carrier by a pin fastening mechanism at an aft end of the integral pin.

5. The gearbox assembly of claim 1 , wherein the integral pin includes an outer surface that defines an inner race of the one or more roller bearings such that the inner race is integral with the integral pin.

6. The gearbox assembly of claim 5, wherein the planet gear defines an outer race of the one or more roller bearings.

7. The gearbox assembly of claim 1 , wherein the planet carrier includes a forward wall and an aft wall, the integral pin including a forward coupling portion and an aft coupling portion, the forward coupling portion being coupled within the forward wall, and the aft coupling portion being coupled within the aft wall.

8. The gearbox assembly of claim 7, wherein the forward coupling portion is press fit into the forward wall, and the aft coupling portion is press fit into the aft wall.

9. The gearbox assembly of claim 7, wherein the forward wall includes a forward pin aperture and the aft wall includes an aft pin aperture, the forward coupling portion being disposed within forward pin aperture, and the aft coupling portion being disposed within the aft pin aperture.

10. The gearbox assembly of claim 9, wherein the forward pin aperture includes a diameter that is greater than a diameter of an outer race of the one or more roller bearings.

11. The gearbox assembly of claim 7, wherein the integral pin includes a middle portion extending between the forward coupling portion and the aft coupling portion, the one or more roller bearings being disposed on the middle portion.

12. The gearbox assembly of claim 11 , wherein the middle portion includes a first pin diameter, the forward coupling portion includes a second pin diameter, and the aft coupling portion includes a third pin diameter, the first pin diameter, the second pin diameter, and the third pin diameter being different.

13. The gearbox assembly of claim 1 , further including one or more lubricant holes extending through the integral pin, wherein lubricant is supplied to the one or more roller bearings through the one or more lubricant holes.

14. The gearbox assembly of claim 13, further including a lubricant sleeve disposed within the integral pin, wherein the lubricant is supplied to the one or more roller bearings from the lubricant sleeve.

15. The gearbox assembly of claim 14, wherein the lubricant sleeve is secured to the integral pin by a lubricant sleeve fastening mechanism.

16. A turbine engine comprising: a low-pressure shaft coupled to a turbine section; a fan shaft coupled to a fan; anda gearbox assembly, the low-pressure shaft transferring torque to the fan shaft through the gearbox assembly, the gearbox assembly comprising: a planet carrier; a planet gear disposed within the planet carrier; one or more roller bearings disposed within the planet gear, the one or more roller bearings including a plurality of rolling elements; and an integral pin disposed within the planet carrier and extending through the planet gear, the integral pin including one or more pin shoulders extending from the integral pin, and the plurality of rolling elements being disposed axially between the one or more pin shoulders and radially between the integral pin and the planet gear, the one or more pin shoulders axially constraining the plurality of rolling elements, wherein the planet gear rotates about the one or more roller bearings with respect to the integral pin.

17. The turbine engine of claim 16, wherein the one or more pin shoulders include a pair of pin shoulders, the plurality of rolling elements being axially constrained between the pair of pin shoulders.

18. The turbine engine of claim 16, wherein the one or more roller bearings include two roller bearings spaced axially on the integral pin.

19. The turbine engine of claim 16, wherein the integral pin is secured to the planet carrier by a pin fastening mechanism at an aft end of the integral pin.

20. The turbine engine of claim 16, wherein the integral pin includes an outer surface that defines an inner race of the one or more roller bearings such that the inner race is integral with the integral pin.

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