Gearbox construction for clockwise and counterclockwise propeller rotation

Abstract

A gear assembly for a turbine includes a sun gear, a plurality of planetary gears, and a ring gear. The gear assembly is connected to an input shaft and an output shaft. The sun gear is configured to rotate about a longitudinal centerline of the gear assembly and is driven by the input shaft. Components of the gear assembly drive the output shaft. The gear assembly further includes an output shaft reversing mechanism configured to reverse the direction of rotation of the output shaft.

Description

Technical Field

[0001] This subject matter generally relates to turbines including gear assemblies, and more specifically, to gear assembly arrangements suitable for reversing the direction of the rotational output of the fan assembly thereby driven. Background Technology

[0002] Gas turbine engines generally rotate their fan blades in the same direction on the aircraft. In some cases, it may be necessary to provide an engine that rotates in different directions. However, it is difficult to reverse the rotation direction of the fan blades in a gas turbine engine without significantly altering the engine or gearbox design. Therefore, turbine modifications are needed to allow the fan blades to rotate in different directions on the same aircraft. Attached Figure Description

[0003] The specification with reference to the accompanying drawings sets forth a complete and feasible disclosure of preferred embodiments for those skilled in the art, wherein:

[0004] Figure 1 This is a cross-sectional schematic diagram of an exemplary embodiment of an open rotor propulsion system;

[0005] Figure 2 This is a cross-sectional schematic diagram of an exemplary embodiment of the pipeline propulsion system;

[0006] Figure 3 This is a schematic diagram of an exemplary gear assembly;

[0007] Figure 4 This is a cross-sectional view of an exemplary planetary gear pair shaft;

[0008] Figure 5 This is a schematic diagram of an exemplary planetary gear countershaft having a first-stage planetary gear and a second-stage planetary gear;

[0009] Figure 6 This is a schematic diagram of an exemplary gear assembly with composite symmetry;

[0010] Figure 7 This is a schematic diagram of an exemplary gear assembly with compound symmetry; for clarity, a portion of the ring gear has been removed.

[0011] Figure 8 This is a schematic diagram of an exemplary planetary carrier with a compound planetary gear.

[0012] Figure 9 This is another schematic diagram of an exemplary planetary carrier with a compound planetary gear;

[0013] Figure 10This is a schematic diagram of a gear assembly with a sun gear, three compound planetary gears and a ring gear, based on an example.

[0014] Figure 11 This is a schematic diagram of a gear assembly with a sun gear, three compound planetary gears, three idler gears and a ring gear, based on another example;

[0015] Figure 12 This is a schematic diagram of an exemplary gear assembly having a ring gear fixed to a turbine housing;

[0016] Figure 13 It is a display Figure 3 A schematic diagram of a portion of the gear assembly;

[0017] Figure 14 The display is modified to drive the output shaft away from the secondary sun gear. Figure 13 A schematic diagram of the gear assembly;

[0018] Figure 15 It has a secondary gear assembly between the core engine's output and input shafts. Figure 13 A schematic diagram of the gear assembly;

[0019] Figure 16 It is based on an example Figure 15 A schematic diagram of the secondary gear assembly.

[0020] Figure 17 It is based on another example Figure 15 A schematic diagram of the secondary gear assembly. Detailed Implementation

[0021] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. Each example is provided as an explanation of the present disclosure and not as a limitation thereof. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present disclosure without departing from the scope or spirit thereof. For example, features shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the present disclosure is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents.

[0022] The term “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as superior to or advantageous to other implementations.

[0023] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of an individual component.

[0024] The terms "front" and "rear" refer to relative positions within a gas turbine engine or vehicle, and to the normal operating posture of the gas turbine engine or vehicle. For example, for a gas turbine engine, "front" refers to the position closer to the engine inlet, and "rear" refers to the position closer to the engine nozzle or exhaust port.

[0025] The terms "upstream" and "downstream" refer to the relative directions of fluid flow within a fluid path. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction from which the fluid flows.

[0026] The terms “connection,” “fixation,” “attachment,” etc., refer to both direct connection, fixation, or attachment, and indirect connection, fixation, or attachment via one or more intermediate components or features, unless otherwise specified herein.

[0027] The singular forms “a,” “a,” and “the” include plural references unless the context clearly indicates otherwise.

[0028] The approximate language used throughout this specification and claims is applied to modify any quantitative representation that may be varied without causing a change in its essential function. Therefore, values ​​modified by one or more terms such as “approximately,” “about,” and “substantially” are not limited to specified exact values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value, or the precision of the method or machine used to construct or manufacture the part and / or system. For example, approximate language may refer to a margin of 1%, 2%, 4%, 10%, 15%, or 20%.

[0029] Throughout this specification and claims, scope limitations are combined and interchanged, and unless the context or language otherwise indicates otherwise, these scopes are identified and include all subscopes contained herein. For example, all scopes disclosed herein include endpoints, and endpoints can be combined independently of each other.

[0030] This document discloses various embodiments of modifications to gear assemblies for rotary engines or turbofan engines. The gear assemblies disclosed herein can reverse the rotation direction of one or more rotary engines. The gear assemblies disclosed herein can provide significant advantages over conventional systems.

[0031] For example, the gear assembly disclosed herein can allow the rotor engines of an aircraft to rotate in opposite directions, thereby reducing or eliminating one or more of the drawbacks associated with rotating engines in the same direction. For instance, when an aircraft has engines rotating in the same direction, one of the engines may eject debris from its operation toward the aircraft fuselage or toward other engines. This necessitates armoring the fuselage against potential impacts that could damage one or more of the aircraft's engines. Rotating the rotor engines in opposite directions, depending on their engine positions, reduces the risk of damage from cross-engine debris by directing the debris flow from all engines away from other engines and the aircraft fuselage. In turn, this reduces the need for armoring or protecting parts of the aircraft against debris, allowing for lighter aircraft weight and avoiding the risk of engine damage from cross-engine debris.

[0032] Rotating the aircraft's rotor engines in opposite directions can further counteract the yaw force that might occur if the engines rotated in the same direction. The rotation of each engine can generate a left or right yaw force depending on the direction of rotation. When the engines rotate in the same direction, these yaw forces may interact additively, creating a persistent yaw effect on the left or right side of the aircraft. When the engines rotate in opposite directions, the yaw forces may partially or completely cancel each other out. As the yaw force is eliminated or reduced, the need to provide reaction forces from other sources may also be eliminated or reduced, which can improve aircraft performance and efficiency.

[0033] Furthermore, when the rotor engines are located near the tip or end of the aircraft wing, operating the engines in opposite directions allows the two engines at the wingtip to rotate in the inward-facing upward direction. This allows for control over the intensity and direction of the wingtip vortices, which can lead to improved wing efficiency.

[0034] Additionally, rotating the aircraft's rotor engines in the opposite direction minimizes aeroacoustic interactions within the cabin space. This reduces noise and discomfort for passengers caused by rotor engine operation and improves the passenger experience.

[0035] By using an alternative gearbox configuration, the direction of rotation can be changed before the turbocharger and / or the core flow path. This minimizes the number of unique components required, and also minimizes component count, reconfiguration needs, the number of spare parts and modules that must be retained for engine maintenance, product cost, and maintenance cost. Additionally, it improves product design flexibility.

[0036] Now refer to the attached diagram, Figure 1This is an exemplary embodiment of an engine 100 including a gear assembly 102 according to aspects of this disclosure. The engine 100 includes a fan assembly 104 driven by a core engine 106. In various embodiments, the core engine 106 is a Brayton cycle system configured to drive the fan assembly 104. The core engine 106 is at least partially covered by a housing 114. The fan assembly 104 includes a plurality of fan blades 108. A blade assembly 110 extends from the housing 114. The blade assembly 110, including a plurality of blades 112, is positioned in an operatively arranged with respect to the fan blades 108 to provide thrust, control thrust vector, reduce or redirect unwanted acoustic noise, and / or otherwise desirously alter airflow relative to the fan blades 108. In some embodiments, the fan assembly 104 includes three (3) to twenty (20) fan blades 108. In a particular embodiment, the fan assembly 104 includes ten (10) to sixteen (16) fan blades 108. In some embodiments, fan assembly 104 includes twelve (12) fan blades 108. In some embodiments, blade assembly 110 includes the same number or fewer blades 112 as the number of fan blades 108.

[0037] In some embodiments, such as in Figure 1 As depicted, the blade assembly 110 is positioned downstream or rearward of the fan assembly 104. However, it should be understood that in some embodiments, the blade assembly 110 may be positioned upstream or forward of the fan assembly 104. In various other embodiments, the engine 100 may include a first blade assembly positioned forward of the fan assembly 104 and a second blade assembly positioned rearward of the fan assembly 104. The fan assembly 104 may be configured to desirably adjust the pitch at one or more fan blades 108, such as to control the thrust vector, reduce or redirect noise, and / or change the thrust output. The blade assembly 110 may be configured to desirably adjust the pitch at one or more blades 112, such as to control the thrust vector, reduce or redirect noise, and / or change the thrust output. Pitch control mechanisms at one or both of the fan assembly 104 and the blade assembly 110 may cooperate to produce one or more of the desired effects described above.

[0038] The core engine 106 is generally enclosed within a housing 114 that defines a maximum diameter. In some embodiments, the engine 100 includes a length from a longitudinal front end 116 to a longitudinal rear end 118. In various embodiments, the engine 100 defines a ratio of length (L) to maximum diameter (Dmax) that provides reduced mounting resistance. In one embodiment, L / Dmax is at least 2. In another embodiment, L / Dmax is at least 2.5. In some embodiments, L / Dmax is less than 5, less than 4, and less than 3. In various embodiments, it should be understood that L / Dmax is used for a single tubeless rotary engine.

[0039] Reduced installation drag can further provide improved efficiency, such as improved fuel consumption rates. Alternatively or additionally, reduced drag can improve engine and aircraft operation at cruise altitudes of Mach 0.5 or higher. In some embodiments, the L / Dmax, fan assembly 104, and / or blade assembly 110 are configured, separately or together, at least partially, for operation at maximum cruise altitude operating speeds between approximately Mach 0.55 and approximately Mach 0.85.

[0040] Refer again Figure 1 The core engine 106 extends in the radial direction R relative to the engine axis centerline 120. The gear assembly 102 receives power or torque from the core engine 106 via a power input source (e.g., input shaft 122) and provides power or torque via a power output source (e.g., output shaft 124) to drive the fan assembly 104 in the circumferential direction C about the engine axis centerline 120.

[0041] In some embodiments, such as Figure 1As depicted, engine 100 is a pipeless thrust generation system, such that the multiple fan blades 108 are not covered by a nacelle or fan casing. Therefore, in various embodiments, engine 100 can be configured as a shielded turbofan engine, an open rotor engine, or a propeller fan engine. In a particular embodiment, engine 100 is a single pipeless rotor engine comprising a single row of fan blades 108. Engine 100 configured as an open rotor engine includes a fan assembly 104 with large-diameter fan blades 108, which can be adapted for high bypass ratios, high cruise speeds (e.g., comparable to, or substantially higher than, those of aircraft with turbofan engines), high cruise altitudes (e.g., comparable to, or substantially higher than, those of aircraft with turbofan engines), and / or relatively low rotational speeds. Cruise altitude is generally the horizontal altitude of the aircraft after climb and before descending into the approach flight phase. In various embodiments, the engine is applied to vehicles with cruise altitudes up to approximately 65,000 feet. In some embodiments, the cruising altitude is between approximately 28,000 feet and approximately 45,000 feet.

[0042] Although described above Figure 1 The gear assemblies disclosed herein are applicable to unshrouded or open rotor engines, but it should be understood that they can be used in shrouded or tubular engines, partially tubular engines, rear-fan engines, or other turbine structures, including those used in marine, industrial, or aerospace propulsion systems. Additionally, the gear assemblies disclosed herein can also be used in turbofan, turboprop, or turboshaft engines.

[0043] For example, Figure 2 This is a cross-sectional schematic diagram of an exemplary embodiment of engine 200, which includes a gear assembly 202 combined with a ducted fan propulsion system. However, with Figure 1 Unlike the open rotor configuration, the fan assembly 204 and its fan blades 208 are contained within an annular fan housing 230, and a blade assembly 210 comprising a plurality of blades 212 extends radially between the fan shroud 232 and the inner surface of the fan housing 230. As discussed above, the gear assembly disclosed herein can provide an increased gear ratio for a fixed gear envelope (e.g., annular gears of the same size), or alternatively, the same gear ratio can be achieved using annular gears of a smaller diameter.

[0044] like Figure 2As shown, the core engine 206 is generally enclosed within a housing 214 and has a length extending from a longitudinal front end 216 to a longitudinal rear end 218. An exemplary core engine (for a piped or pipeless engine) may include a compressor section 240, a heat-addition system 242 (e.g., a combustor), and an expansion section 244 arranged together in a serial flow configuration. The core engine 206 extends circumferentially relative to the engine centerline axis 220. The core engine 206 includes a high-speed spool comprising a high-speed compressor and a high-speed turbine operably and rotatably coupled together by a high-speed shaft. The heat-addition system 242 is positioned between the high-speed compressor and the high-speed turbine. Various embodiments of the heat-addition system 242 include a combustion section. The combustion section may be configured as a detonation combustion section, a rotary detonation combustion section, a pulse detonation combustion section, or other suitable heat-addition system. The heat-addition system 242 may be configured as a rich combustion system or a lean combustion system, or a combination thereof, or one or more of these. In other embodiments, the heat addition system 242 includes an annular burner, a canister burner, an annular tube burner, a vortex burner (TVC) or other suitable combustion systems, or combinations thereof.

[0045] The core engine 206 may also include a turbocharger or a low-speed compressor positioned in flow relationship with the high-speed compressor. The low-speed compressor is rotatably coupled to a low-speed turbine via a low-speed shaft 246, enabling the low-speed turbine to drive the low-speed compressor. The low-speed shaft 246 is also operatively connected to a gear assembly 202 to power the fan assembly 204 via a power input source (e.g., input shaft 222), as further described herein.

[0046] It should be understood that the terms “low” and “high,” or their corresponding comparatives (e.g., lower, higher where applicable), when used with compressor, turbine, shaft, or spool components, each refer to a relative speed within the engine, unless otherwise specified. For example, “low turbine” or “low-speed turbine” defines a component configured to operate at a lower speed (such as the maximum permissible speed) than a “high turbine” or “high-speed turbine” in the engine. Alternatively, unless otherwise specified, the above terms may be understood as superlatives. For example, “low turbine” or “low-speed turbine” may refer to a turbine with the lowest maximum speed within a turbine section, “low compressor” or “low-speed compressor” may refer to a compressor with the lowest maximum speed within a compressor section, “high turbine” or “high-speed turbine” may refer to a turbine with the highest maximum speed within a turbine section, and “high compressor” or “high-speed compressor” may refer to a compressor with the highest maximum speed within a compressor section. Similarly, a low-speed spool refers to a maximum speed lower than a high-speed spool. It should be further understood that the terms “low” or “high” in these respects may be interpreted, in addition to or alternatively, as relative to the minimum permissible speed, or relative to the minimum or maximum permissible speed of the engine in its normal, desired, stable, or otherwise operating condition.

[0047] As discussed in more detail below, the core engine 206 includes a gear assembly configured to transmit power from the expansion section 244 and reduce the output speed at the fan assembly 204 relative to the low-speed turbine. Embodiments of the gear assembly depicted and described herein can allow for application to large-diameter ductless fans (e.g., Figure 1 ) or certain turbo fans (e.g., Figure 2 The gear ratio is [missing information]. Furthermore, the embodiments of the gear assembly provided herein can be applied to radial or diametrical constraints of the core engine within the housing.

[0048] The gear assembly described herein includes a set of gears for reducing the rotational speed of the fan assembly relative to the low-speed (pressure) turbine. In operation, the rotating fan blades are driven by the low-speed (pressure) turbine via the gear assembly, causing the fan blades to rotate about the engine's centerline and generate thrust to drive the engine, thereby propelling the aircraft on which the engine is mounted in the forward direction.

[0049] Figure 5 One or more secondary pins 326 and compound planetary gears 306, 308 are shown. Figure 6 and 7 The diagram shows the secondary shaft pin 326, compound planetary gears 306 and 308, and the sun gear 304, with a ring gear 310 ( Figure 6 ) and removed part of the ring gear ( Figure 7 ).exist Figure 6 and 7 In the illustrated embodiment, three compound planetary gears (306, 308) are provided, and the ring gear 310 includes two halves having interconnecting flange portions 328. Figure 7 Multiple radial channels for oil scavenging were also disclosed.

[0050] For clarity, Figure 8 and 9 A planetary gear carrier 324 in which a single compound planetary gear (306, 308) is disposed is shown. A counterspin pin 326 extends through openings in the front and rear sides of the planetary gear carrier 324. In some embodiments, the carrier may be connected to the engine frame via a flexible support system configured to collect and remove oil through holes in the lower portion.

[0051] In some embodiments, the gear ratio allocation between the first stage and the second stage can range from 40% to 60% for each stage (i.e., from 40% to 60% for the first stage and from 60% to 40% for the second stage).

[0052] As discussed above, in some embodiments, the sun gear 304, planet gears 306, 308 and ring gear 310 may be double helical gears having a first set of helical teeth and a second set of helical teeth inclined at an acute angle relative to each other.

[0053] exist Figure 3 In the illustrated embodiment, gear assembly 302 is a star gear configuration, wherein the planetary carrier is generally fixed (e.g., stationary) within the engine by a support structure. The sun gear 304 is driven by an input shaft 332 (e.g., a low-speed shaft). The planetary carrier 324 is rotatably coupled to the countershaft of compound planetary gears 306, 308, and the ring gear 310 is configured to rotate circumferentially about the longitudinal engine axis centerline 340, which in turn drives a power output source (e.g., a fan shaft), which is coupled to the ring gear and configured to rotate together with the ring gear to drive the fan assembly. In this embodiment, the low-speed shaft 332 rotates in a circumferential direction opposite to the direction of rotation of the fan drive shaft 330.

[0054] In other embodiments, the gear assembly may have a planetary configuration, wherein the ring gear is fixed (e.g., stationary) within the engine by a support structure. The sun gear is driven by the input shaft (i.e., the low-speed shaft) and rotates in place of the ring gear, while the planet carrier rotates in the same direction as the low-speed shaft to drive the power output source (e.g., the fan shaft) and the fan assembly.

[0055] Refer again Figure 3 A ring gear 310 is coupled to a fan drive shaft 330 to drive the fan. A sun gear 304 is coupled to an input power source (e.g., an input shaft 332). In some embodiments, the input shaft may be integrally formed with the sun gear. The double-helix meshing of the planetary gears axially balances the load on the four (phased) gear sets of each compound planetary gear. The second-stage planetary gear 308 may be supported by two rows of cylindrical roller bearings 334 at the planetary bore. Additionally, the fan drive shaft 330 may be supported by tapered roller bearings or helical ball bearings 338, which support the fan drive shaft 330 in an axially compact manner. In some embodiments, the roller bearings 334 may be formed of a ceramic material. In some embodiments, the roller bearings 334 may be lubricated by under-race lubrication, wherein the lubricant is guided under the inner race and extruded through multiple holes in the inner race. In some embodiments, as... Figure 3 As shown, the inner support elements of the two sets of roller bearings 334 can be solid, unique elements.

[0056] In some embodiments, one of a pair of gear sets (e.g., one of a first gear set and a second gear set, a third gear set, or a fourth gear set) is angularly synchronized relative to the other gear set by a predetermined amount of gear pitch. For example, the teeth of the first gear set may be angularly synchronized relative to the teeth of the second gear set by a first amount of gear pitch. The first amount may be between one-quarter and one-half. Similarly, the teeth of the third gear set may be angularly synchronized relative to the teeth of the fourth gear set by a second amount of gear pitch. The second amount may also be between one-quarter and one-half.

[0057] The following are exemplary gear assemblies that, according to examples disclosed herein, can reverse the direction of rotation of a turbofan engine. Thus, an aircraft may include at least one turbofan engine rotating in a first direction and at least one turbofan engine rotating in a second direction. For example, an aircraft with a pair of turbofan engines may include a first turbofan engine having fan blades rotating in a first direction of rotation (e.g., clockwise or counterclockwise) and a second turbofan engine having fan blades rotating in a second direction of rotation (e.g., clockwise or counterclockwise), the second direction of rotation being opposite to the first direction of rotation. For an aircraft with more than two turbofan engines, turbofan engines on the same side of the aircraft body may rotate relative to each other in the same direction or in different directions. Such an assembly may replace or be used with any of the gear assemblies previously described and can be incorporated into any engine design, including those discussed above.

[0058] In one embodiment, the direction of the second turbofan engine in a pair of turbofan engines can be reversed, while maintaining a fundamentally similar construction of the engine components by introducing multiple idler gears into the gear assembly that drives the fan blades of the turbofan engine. Figure 10 and 11 Two exemplary gear assembly configurations are shown for reversing the rotation direction of one turbofan engine relative to the rotation direction of the other turbofan engine in a pair of turbofan engines.

[0059] Figure 10 This shows a similar design used in the first turbofan engine of a pair of turbofan engines. Figure 6 and 7The rotary gear assembly 400 is shown. The gear assembly 400 may be a star-shaped configuration having a ring gear 402, three compound planetary gears 404, and a sun gear 410, the three compound planetary gears 404 having a first stage 406 and a second stage 408. In operation, the sun gear 410 is driven in a first rotational direction (e.g., clockwise or counterclockwise) via an input shaft driven by the core engine output of a first engine. The sun gear 410 engages with the first stage 406 of the planetary gears 404, causing the first stage 406 and the second stage 408 of the planetary gears to rotate in a second rotational direction opposite to the first rotational direction (e.g., counterclockwise or clockwise). The second stage of the planetary gears 408 engages with the ring gear 402, causing the ring gear 402 to also rotate in the second rotational direction (e.g., counterclockwise or clockwise). The ring gear 402 is configured to drive the fan assembly of a turbofan engine (such as turbofan engine 100 or 200) in the second rotational direction (e.g., clockwise or counterclockwise). Thus, the fan assembly of the first engine is driven in the opposite direction of rotation to the input shaft from the core engine output of the first engine. Although Figure 10 The example shown illustrates a gear assembly with three compound planetary gears 404, but it should be understood that a smaller number of compound planetary gears (such as two or one compound planetary gear) or a larger number of planetary gears (such as four, five or six planetary gears) may also be used.

[0060] Gear assembly 400 may have a gear ratio between the input and output shafts, ranging from 6:1 to 14:1, from 6:1 to 12:1, from 7:1 to 11:1, or from 8:1 to 10:1. In certain specific examples, gear assembly 400 may have gear ratios of 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, or any gear ratio in between. In one example, the gear assembly has a gear ratio of 8.7:1.

[0061] Figure 11Another planetary gear assembly 500 suitable for use with the second engine in a pair of turbofan engines is shown. The gear assembly 500 has a ring gear 502, three compound planetary gears 504, a plurality of idler gears 510, and a sun gear 512. The three compound planetary gears 504 have a first stage 506 and a second stage 508. In operation, the sun gear 512 is driven by a turbine in a first rotational direction (e.g., clockwise or counterclockwise). The sun gear 512 engages with the first stage 506 of the planetary gears 504, causing the first stage 506 and the second stage 508 of the planetary gears to rotate in a second rotational direction opposite to the first rotational direction (e.g., counterclockwise or clockwise). The second stage 508 of the planetary gears engages with the idler gears 510, causing the idler gears 510 to rotate in the first rotational direction (e.g., clockwise or counterclockwise). The idler gears 510 engage the ring gear 502, causing the ring gear 502 to rotate in the first rotational direction (e.g., clockwise or counterclockwise). The ring gear 502 is configured to drive the rotating fan blades of a turbofan engine (such as turbofan engine 100 or 200) in a first rotational direction (e.g., clockwise or counterclockwise). Thus, the fan assembly of the second engine is driven in the same rotational direction as the input shaft from the core engine output of the second engine. Although Figure 11 The example shown illustrates a gear assembly with three compound planetary gears 504; however, it should be understood that a smaller number of compound planetary gears (such as two or one compound planetary gear) or a larger number of planetary gears (such as four, five, or six planetary gears) may also be used. It should also be understood that a smaller number of idler gears (such as two or one idler gear) or a larger number of idler gears (such as four, five, or six idler gears) may also be used.

[0062] Because the idler gear 510 is positioned between the second stage 508 of the planetary gear 504 and the ring gear 502, it may experience cyclic fatigue in two directions compared to the one direction experienced by the planetary gear 504. To address this additional cyclic stress, in some examples, the ring gear 502, planetary gear 504, idler gear 510, and sun gear 512 can be made with larger gear modules (i.e., with thicker teeth) to improve the expected service life of the components before failure requires repair or replacement.

[0063] Similar to gear assembly 400, gear assembly 500 may have a gear ratio between the input and output shafts, ranging from 6:1 to 14:1, from 6:1 to 12:1, from 7:1 to 11:1, or from 8:1 to 10:1. In certain specific examples, gear assembly 500 may have gear ratios of 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, or any gear ratio in between. In one example, the gear assembly has a gear ratio between 8.7:1 and 8.9:1. Preferably, gear assemblies 400 and 500 have the same or similar gear ratios (e.g., within 5% of each other).

[0064] In this way, different turbofan engines on the same aircraft (e.g., turbofan engines 100 and 200) can cause their respective fan assemblies to rotate in different directions. Furthermore, since the gear assemblies are similar except for the idler gear and related aspects, each gear assembly in the two assemblies can use common parts, reducing the number of parts required to assemble and maintain the engine, and the two gear assemblies can achieve the same or similar output.

[0065] In another embodiment, by arranging the gearbox of one engine in a radial configuration and the gearbox of the other engine in a planetary configuration, the direction of at least one turbofan engine can be reversed relative to at least one other turbofan engine of the aircraft. Thus, for example, the first engine in a pair of engines may include a radially configured gear assembly (having a fixed or stationary planetary gear carrier and a rotating ring gear attached to the engine's power output shaft), and the second engine may include a planetary configuration gear assembly (with a fixed or stationary ring gear and a rotating planetary gear carrier attached to the engine's power output shaft).

[0066] The first engine may include a planetary gear assembly in a star-shaped configuration, such as Figure 3The components are shown. As discussed above, the sun gear 304 of gear assembly 302 is coupled to an input power source (e.g., input shaft 332), and in some embodiments, may be integrally formed with the input shaft 332. The sun gear 304 rotates in a first rotational direction (e.g., clockwise or counterclockwise) and engages with the first gear set 312 and the second gear set 314 of the first-stage planetary gear 306, which rotates in a second rotational direction opposite to the first rotational direction (e.g., counterclockwise or clockwise). The third gear set 316 and the fourth gear set 318 of the second-stage planetary gear 308 engage with the first ring gear set 320 and the second ring gear set 322 of the ring gear 310, which rotate in the second rotational direction (e.g., counterclockwise or clockwise). A ring gear 310 is fixed to a fan drive shaft 330, which drives a power output source (e.g., a fan shaft 330) that is coupled to and configured to rotate with the ring gear to drive the fan assembly in a second rotational direction (e.g., counterclockwise or clockwise). Thus, the fan assembly of the first engine is driven in the opposite rotational direction to the input shaft from the core engine output of the first engine. In some examples, the ring gear 310 may be attached to the fan drive shaft 330 via multiple pins or bolts 336.

[0067] The gear assembly of the first engine may have a gear ratio between the input and output shafts, ranging from 6:1 to 14:1, from 6:1 to 12:1, from 7:1 to 11:1, or from 8:1 to 10:1. In certain specific examples, gear assembly 400 may have a gear ratio of 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, or any gear ratio in between. In one example, the gear assembly has a gear ratio of 8.7:1.

[0068] The second engine in a pair of engines may include a planetary gear assembly, such as... Figure 12The example shown illustrates this. Gearbox 600 has a sun gear 602, a plurality of compound planetary gears 604, a planetary carrier 606, and a stationary ring gear 608. The sun gear 602 is coupled to an input power source (e.g., an input shaft 610) that drives the sun gear 602 in a first rotational direction (e.g., clockwise or counterclockwise). In some embodiments, the sun gear 602 may be integrally formed with the input shaft 610. The compound planetary gears 604 are held within the planetary carrier 606. The sun gear 602 engages a first stage 612 of each compound planetary gear 604 that rotates in a second rotational direction (e.g., counterclockwise or clockwise), the second rotational direction being opposite to the first rotational direction. The planetary gears 604 have a second stage 614 that engages with the ring gear 608. The compound planetary gear 604 travels in the ring gear in the opposite direction to its own rotation. That is, the planetary gear 604, which rotates clockwise, will travel counterclockwise in the ring gear 608, and the compound planetary gear 604, which rotates counterclockwise, will travel clockwise in the ring gear 608.

[0069] The ring gear 608 can be fixed to the engine housing or a flexible support system and will not rotate relative to the engine housing. In some examples, the ring gear 608 can be fixed to a stationary engine housing 616. In this way, the ring gear 608 remains stationary relative to the engine housing 616, and the planetary gear carrier 606 moves together with the planetary gears 604 in the first rotational direction. The planetary gear carrier 606 is attached to a power output source (e.g., fan shaft 618) that drives the fan assembly in the first rotational direction. Thus, the fan assembly of the second engine is driven in the same rotational direction as the input shaft from the core engine output of the first engine.

[0070] In this embodiment, both the first and second engine gear assemblies can have gear ratios ranging from 7:1 to 15:1, from 7:1 to 13:1, from 8:1 to 12:1, or from 9:1 to 11:1. In certain specific examples, gear assembly 600 can have gear ratios of 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, or any gear ratio in between. In one example, the gear assembly has a gear ratio of 9.7:1. Because in some examples the gear ratio of gear assembly 600 can be higher than that of gear assembly 300, for example, by 1, it may be necessary to use gear assembly 600 to operate any engine at different input speeds supplied by the core engine driving the second engine in a pair of engines, so that the fan assemblies of the first and second engines rotate at equal speeds. Alternatively, the star gear assembly can be resized to accommodate a higher gear ratio (e.g., equal to or close to the gear ratio of a planetary gear assembly), or the secondary gear assembly can be included in the second engine, which modifies the rotational speed of the core engine output of one of the turbofan engines (e.g., the second turbofan engine) so that the rotational speed of the input shaft 610 differs from that of the input shaft 332 in order to compensate for the difference in the gear ratio of the gear assembly.

[0071] In this way, the aircraft's turbofan engines (e.g., turbofan engines 100, 200) can be configured such that the fan assembly of the first engine rotates in the opposite direction to the rotational direction of the core engine output of the first engine, and the fan assembly of the second engine rotates in the same direction as the rotational direction of the core engine output of the second engine. Advantageously, this option can be implemented using almost identical engine components for the two gear assemblies, only changing which engine components are attached to the gear carrier and the ring gear, and combining additional components or secondary gear assemblies to make the rotational speeds of the fan assemblies of the first and second engines equal.

[0072] Figure 13 and 14 Another embodiment of a gear assembly configured to provide rotation of the fan assembly in different directions is shown. In this example, the power output source of at least one turbofan engine (e.g., a fan shaft) can be coupled to a second sun gear, which engages with a second-stage planetary gear of a plurality of compound planetary gears. Thus, the rotational direction of the power output source of at least one engine will be reversed relative to the rotational direction of at least one other engine of the aircraft.

[0073] According to one example solution, the first engine may include a revolute gear assembly similar to gearbox assembly 302. Figure 13A schematic diagram of a gear assembly 700 of a first engine is shown. The gear assembly 700 includes a sun gear 702 driven by an input shaft 704. In some embodiments, the sun gear 702 and the input shaft 704 may be integrally formed. The sun gear 702 rotates in a first rotational direction (e.g., clockwise or counterclockwise) and engages a first stage 706 of each of a plurality of compound planetary gears 708 that rotates in a second rotational direction (e.g., counterclockwise or clockwise), the second rotational direction being opposite to the first rotational direction. The compound planetary gears 708 have a second stage 710 that rotates together with the first stage 706 and engages a ring gear 712. The ring gear 712 is disposed radially outward from the compound planetary gears 708 and engages the second stage 710 of the compound planetary gears at a radially outward 714. The ring gear 712 rotates together with the compound planetary gears 708 in the second rotational direction (e.g., counterclockwise or clockwise). The ring gear 712 is coupled to be configured to rotate together with the drive shaft 716, which drives a power output source (such as a fan shaft) and drives the fan assembly of a turbofan engine.

[0074] Now go to Figure 14 The diagram shows a schematic of a gear assembly suitable for use with a second engine. The gear assembly 800 includes a first sun gear 802 driven by an input shaft 804. In some embodiments, the sun gear 802 and the input shaft 804 may be integrally formed. The sun gear 802 rotates in a first rotational direction (e.g., clockwise or counterclockwise) and engages a first stage 806 of each of a plurality of compound planetary gears 808 that rotates in a second rotational direction (e.g., counterclockwise or clockwise), the second rotational direction being opposite to the first rotational direction. The compound planetary gears 808 have a second stage 810 that rotates together with the first stage 806 and engages a second sun gear 812 at a radially inward surface 814. The second sun gear 812 is positioned radially inward from the second stage 810 of the plurality of compound planetary gears 808 and rotates in the first rotational direction (e.g., clockwise or counterclockwise). The second sun gear 812 can be attached to a connecting frame 816, which extends from the second sun gear 812 to a drive shaft 818 that drives a power output source (such as a fan shaft) and drives the fan assembly of a turbofan engine.

[0075] The gear ratios of both the first and second engines can range from 6:1 to 14:1, from 6:1 to 12:1, from 7:1 to 11:1, or from 8:1 to 10:1. In certain specific examples, gear assembly 400 can have gear ratios of 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, or any gear ratio in between.

[0076] Therefore, a turbofan engine can be configured such that the fan assembly of the first engine rotates in the opposite direction to the rotation of the fan assembly of the second engine. Advantageously, many components of the two gear assemblies can be identical or similar. Thus, the two engines can have similar performance characteristics (such as efficiency, size, weight, and number of parts) and require only minimal adjustments to make the engine output performance equal.

[0077] In another embodiment, the direction of at least one fan assembly of the aircraft can be reversed relative to at least one other fan assembly of the aircraft by using a secondary gearbox between the input shaft of the primary gearbox and the core engine. In this way, the rotation direction of the fan assembly of the second engine in a pair of engines can be reversed, while using the same or similar primary gearbox and the same core engine construction for both engines.

[0078] According to one example, the first engine may include, for example, Figure 3 The gearbox assembly 302 shown is a similar gear assembly. As discussed above, the sun gear 304 of the gear assembly 302 is coupled to an input power source (e.g., input shaft 332), and in some embodiments, may be integrally formed with the input shaft 332. The sun gear 304 rotates in a first rotational direction (e.g., clockwise or counterclockwise) and engages the first gear set 312 and the second gear set 314 of the first stage planetary gear 306, which rotates in a second rotational direction (e.g., counterclockwise or clockwise), opposite to the first rotational direction. The third gear set 316 and the fourth gear set 318 of the second stage planetary gear 308 engage the first ring gear set 320 and the second ring gear set 322 of the ring gear 310, which rotates in the second rotational direction (e.g., counterclockwise or clockwise). The ring gear 310 is fixed to the fan drive shaft 330, which drives a power output source (e.g., fan shaft 330). The power output source is coupled to the ring gear and configured to rotate with the ring gear to drive the fan assembly in a second rotational direction (e.g., counterclockwise or clockwise).

[0079] Now go to Figure 15 The second engine may include a primary gear assembly (e.g., gear assembly 302) similar to that in the first engine, and a secondary gear assembly (e.g., secondary gears 900, 1000) located between the core engine and the input shaft 332. In some examples, the secondary gear assembly may be another planetary gear, such as the planetary gear 900 in a star configuration shown in more detail. Figure 16As shown, the secondary gear assembly 900 may include a secondary gear input shaft 902, a sun gear 904, a plurality of planetary gears 906, and a ring gear 908. The secondary gear input shaft 902 connects the core engine to the sun gear 904, driving the sun gear 904 in a first rotational direction (e.g., clockwise or counterclockwise). In some embodiments, the sun gear 904 may be integrally formed with the secondary gear input shaft 902. The planetary gears 906 engage simultaneously with the rotating sun gear 904 and the ring gear 908, and rotate in a second rotational direction (e.g., counterclockwise or clockwise), the second rotational direction being opposite to the first rotational direction. The ring gear 908 is driven by the planetary gears and rotates in the second rotational direction (e.g., counterclockwise or clockwise), driving the secondary gear output shaft 910 in the second rotational direction.

[0080] The secondary gear output shaft 910 can be configured to serve as the input shaft of the primary gear assembly (e.g., input shaft 332 of gear assembly 302). In this way, the secondary gear assembly can reverse the rotational direction of the core engine input before it reaches the primary gear assembly, thereby reversing the rotational direction of the fan assembly of the second engine to a second rotational direction. It should be understood that, although... Figure 16 The secondary gear assembly 900 in a star configuration is shown, but this is merely an exemplary illustration and any secondary gear assembly capable of reversing the rotational output of the core engine can be used instead.

[0081] In this example, the overall combined gear ratio of the primary gear assembly 302 and the secondary gear assembly 900 of the second engine should be equal to or approximately equal to the gear ratio of the gear assembly of the first engine. For example, if the gear assembly of the first engine has a gear ratio of 9:1, then the second engine can use a primary gear assembly 302 with a gear ratio of 4.5:1 and a secondary gear assembly 900 with a gear ratio of 2:1.

[0082] In some examples, the secondary gear assembly can have a 1:1 gear ratio. Figure 17 The illustration shows an alternative example of a secondary gear assembly 1000 with a gear ratio of 1:1. (As shown...) Figure 17As shown, the secondary gear assembly 1000 may include an input shaft 1002, a drive gear 1004, a first idler gear 1006, a second idler gear 1008, an output gear 1010, and an output shaft 1012. The input shaft 1002 connects the core engine to the drive gear 1004, causing it to rotate in a first rotational direction (e.g., clockwise or counterclockwise). The drive gear 1004 may engage with the first idler gear 1006, driving the first idler gear 1006 in a second rotational direction opposite to the first rotational direction (e.g., counterclockwise or clockwise). The first idler gear 1006 may engage with the second idler gear 1008, driving the second idler gear 1008 in the first rotational direction. The second idler gear 1008 may engage with the output gear 1010, driving the output gear 1010 in the second rotational direction. The output gear 1010 is attached to the output shaft 1012 (which may also be the input shaft 332 of the primary gear assembly 302), driving the output shaft 1012 in the second rotational direction. Figure 17 In the example shown, the drive gear 1004 and the output gear 1010 can have the same pitch diameter and tooth geometry, such that the gear ratio between the drive gear 1004 and the output gear 1010 can be 1:1. Thus, the input and output shafts of the secondary gear assembly 1000 rotate in opposite directions but at the same rotational speed. In this example, the primary gear assembly 302 of the second engine and the gear assembly of the first engine can be identical.

[0083] Advantageously, this solution allows the use of the same primary gear assembly in both the first and second engines of a pair of engines. Instead, the difference in fan rotation is created by making the input shaft rotate in the opposite direction to the secondary gear assembly.

[0084] When the rotation direction of one or more fan components is reversed according to any of the options discussed above, several drawbacks of gas turbine engines can be mitigated or corrected with minimal changes to the overall engine design.

[0085] For example, the yaw force introduced by each engine can be reversed, allowing the yaw forces of engines operating in opposite directions of rotation to cancel each other out, reducing or eliminating aircraft yaw and improving aircraft operational efficiency. Furthermore, the ability to select the direction of rotation of engines located near the wingtip allows for attenuation of wingtip vortices, leading to further improvements in operational efficiency.

[0086] For open rotor engines operating in opposite directions, potential debris from the engines can be projected away from the fuselage or adjacent engines, reducing the likelihood of damage from cross-engine debris. Additionally, airflow leaving all engines can be directed away from the aircraft cabin, reducing unwanted noise and turbulence in the passenger cabin.

[0087] Because these results can be achieved with minimal changes to the gearbox design disclosed herein, these favorable results can be obtained without significantly increasing the manufacturing or maintenance costs of the aircraft.

[0088] This written description uses examples to disclose this embodiment, including the best mode, and also enables any person skilled in the art to practice this disclosure, including making and using any device or system, and any method of combination. The patentable scope of this disclosure is defined by the claims, and may include other examples that would occur to a person skilled in the art. Such other examples are intended to fall within the scope of the claims if they include structural elements that are not indistinguishable from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

[0089] Further aspects of this disclosure are provided by the subject matter of the following provisions:

[0090] Clause 1. A turbine engine comprising: a fan assembly including a plurality of fan blades; a core engine including a turbine and an input shaft, the input shaft being rotatable with the turbine and configured to rotate in a first rotational direction; a first gear assembly receiving the input shaft at a first speed and driving an output shaft coupled to the fan assembly at a second speed slower than the first speed, the gear assembly including a sun gear, a plurality of planetary gear countershafts each supporting a first-stage planetary gear and a second-stage planetary gear, and a ring gear, the sun gear being disposed around a longitudinal centerline of the gear assembly; and an engine output reversing mechanism configured to reverse the rotational motion of the fan assembly from the second rotational direction to the first rotational direction, the second rotational direction being opposite to the first rotational direction, wherein the first-stage planetary gears include a first gear set and a second gear set supported at the planetary gear countershafts, and the second-stage planetary gears include a third gear set supported at a first outer portion of the planetary gear countershafts and a fourth gear set supported at a second outer portion of the planetary gear countershafts.

[0091] Clause 2. A turbine engine pursuant to any of the provisions herein, particularly Clause 1, wherein the engine output reversing mechanism is a plurality of idler gears disposed between and engaging with the second-stage planetary gears and the ring gear, and configured to rotate in the opposite direction to the planetary gears.

[0092] Clause 3. A turbine engine pursuant to any of the provisions herein, particularly Clause 1, wherein the engine output reversing mechanism is a second sun gear, the second sun gear being radially disposed within and engaging with the second stage planetary gear and configured to drive the output shaft, and wherein the ring gear is disengaged from the second stage planetary gear.

[0093] Clause 4. The turbine engine pursuant to any of the provisions herein, particularly Clause 1, wherein the engine output reversing mechanism is a secondary gear assembly configured to reverse the direction of rotation of the input shaft.

[0094] Clause 5. A turbine engine pursuant to any of the provisions herein, particularly Clause 4, wherein the secondary gear assembly is a planetary gear assembly having a rotating ring gear having a 1:1 ratio.

[0095] Clause 6. A turbine engine pursuant to any of the provisions herein, particularly Clause 1, wherein the first gear assembly is a planetary gear in a star gear configuration, wherein the first-stage planetary gear and the second-stage planetary gear are contained within a gear carrier, and the gear carrier is fixed and does not rotate relative to the turbine engine, and the ring gear is configured to drive the output shaft.

[0096] Clause 7. A turbine engine pursuant to any of the provisions herein, particularly Clause 1, wherein the first gear assembly is a planetary gear assembly in a planetary configuration, wherein the ring gear is fixed relative to the turbine engine and does not rotate, and the planetary gears travel in the rotational direction within the ring gear and are configured to move together with a gear carrier, the gear carrier being configured to drive the output shaft.

[0097] Clause 8. A turbine engine pursuant to any of the provisions herein, particularly Clause 7, wherein the turbine engine further comprises a second gear assembly configured to change the rotational speed of the input shaft.

[0098] Clause 9. The turbine described in any of the preceding clauses, in particular the first gear assembly, wherein the gear ratio of the first gear assembly ranges from 6:1 to 14:1, from 6:1 to 12:1, from 7:1 to 11:1, or from 8:1 to 10:1.

[0099] Clause 10. The turbine described in any of the provisions herein, and in particular any of the foregoing provisions, wherein the fan assembly is a single-stage ductless fan blade.

[0100] Clause 11. The turbine described in any of the provisions herein, and in particular any of the foregoing provisions, has three planetary gear countershafts.

[0101] Clause 12. An aircraft comprising: a first turbofan engine having a first core engine, a first core engine output shaft rotating in a first rotational direction, a first gear assembly, and a first output shaft rotating in a second rotational direction to drive a first fan assembly; and a second turbofan engine having a second core engine, a second core engine output shaft rotating in the first rotational direction, a second gear assembly, and a second output shaft rotating in the first rotational direction to drive a second fan assembly, wherein the first gear assembly receives the first core engine output shaft at a first speed and drives the first output shaft at a second speed lower than the first speed; and wherein the second gear assembly receives the second core engine output shaft at a third speed and drives the second output shaft at a fourth speed lower than the third speed.

[0102] Clause 13. An aircraft pursuant to any of the provisions herein, particularly Clause 12, wherein the first gear assembly comprises a sun gear, a plurality of planetary gears, and a first ring gear, wherein the sun gear engages the planetary gears, the planetary gears engage the first ring gear, and the first ring gear drives the first output shaft; and the second gear assembly comprises a sun gear, a plurality of planetary gears, a plurality of idler gears, and a second ring gear, wherein the sun gear engages the planetary gears, the planetary gears engage the idler gears, the idler gears engage the second ring gear, and the second ring gear drives the second output shaft.

[0103] Clause 14. The aircraft described in any of the provisions herein, especially Clause 12, wherein the number of the plurality of idler gears in the second gear assembly is equal to the number of planetary gears in the second gear assembly.

[0104] Clause 15. An aircraft pursuant to any of the provisions herein, particularly Clause 12, wherein: the first gear assembly comprises a sun gear, a plurality of planetary gears, a first gear carrier, and a first ring gear, wherein the planetary gears are held in the gear carrier, the gear carrier being attached to a fixed engine housing, the sun gear engaging the planetary gears, the planetary gears engaging the first ring gear, and the first ring gear driving the first output shaft; and the second gear assembly comprises a sun gear, a plurality of planetary gears, a second gear carrier, and a second ring gear, wherein the planetary gears are held in the gear carrier, the second ring gear being attached to a fixed engine housing, the sun gear engaging the planetary gears, the planetary gears engaging the second ring gear, and the second gear carrier driving the second output shaft.

[0105] Clause 16. An aircraft pursuant to any of the provisions herein, particularly Clause 12, wherein: the first gear assembly comprises a sun gear, a plurality of planetary gears, and a ring gear, wherein the sun gear engages with the planetary gears, the planetary gears engage with the ring gear, and the ring gear drives the first output shaft; and the second gear assembly comprises a first sun gear, a plurality of planetary gears, and a second sun gear, wherein the first sun gear engages with the planetary gears, the planetary gears engage with the second sun gear, and the second sun gear drives the second output shaft.

[0106] Clause 17. An aircraft pursuant to any of the provisions herein, particularly Clause 12, wherein the second turbofan engine includes a third gear assembly located between the second core engine and the second gear assembly, the third gear assembly being configured to reverse the direction of rotation of the output shaft of the second core engine.

[0107] Clause 18. The aircraft described in any of the provisions herein, especially Clause 17, wherein the third gear assembly has a gear ratio of 1:1.

[0108] Clause 19. The turbine pursuant to any of the provisions herein, and in particular any of the foregoing provisions, wherein the gear ratio of the first gear assembly ranges from 6:1 to 14:1, from 6:1 to 12:1, from 7:1 to 11:1, or from 8:1 to 10:1, and the gear ratio of the second gear assembly ranges from 6:1 to 15:1.

[0109] Clause 20. An aircraft pursuant to any of the provisions herein, particularly Clause 12, wherein the first fan assembly and the second fan assembly each comprise a single-stage ductless fan blade.

[0110] Clause 21. An aircraft pursuant to any of the provisions herein, particularly Clause 12, wherein the first fan assembly and the second fan assembly each comprise a single-stage duct fan blade.

[0111] Clause 22. A method for reversing the rotational direction of one of a pair of fan assemblies, comprising: driving the first fan assembly in a first rotational direction using inputs from a first core engine to a first gear assembly and outputs from the first gear assembly to the first fan assembly; driving the second fan assembly in a second rotational direction using inputs from a second core engine to a second gear assembly and outputs from the second gear assembly to the second fan assembly; and reversing the second rotational direction using a reversing mechanism disposed between the second core engine and the second fan assembly, wherein the reversing mechanism comprises at least one of: a plurality of idler gears configured to reverse the outputs of the second gear assembly; a secondary sun gear disposed in the second gear assembly and configured to reverse the outputs of the second gear assembly; a planetary gear carrier disposed in the second gear assembly and connected to the second fan assembly and configured to reverse the outputs of the second gear assembly; or a third gear assembly disposed between the second core engine and the second gear assembly and configured to reverse the rotational inputs of the second gear assembly.

[0112] Given the many possible embodiments to which the principles of this disclosure can be applied, it should be understood that the illustrated embodiments are merely preferred examples of this disclosure and should not be considered as limiting the scope of this disclosure. Rather, the scope of this disclosure is defined by the following claims.

Claims

1. A turbine engine, characterized in that, include: Fan assembly, the fan assembly including a plurality of fan blades; A core engine, the core engine including a turbine and a core engine output shaft, the core engine output shaft being rotatable together with the turbine and configured to rotate in a first rotational direction; Secondary gear assembly, which is connected to and driven by the core engine, and drives the secondary gear output shaft in a second rotational direction opposite to the first rotational direction; and A first gear assembly receives and is driven by the secondary gear output shaft at a first speed, and is driven to the output shaft of the fan assembly at a second speed slower than the first speed. The first gear assembly includes a sun gear, a plurality of planetary gear countershafts each supporting a first-stage planetary gear and a second-stage planetary gear, and a ring gear. The sun gear is arranged around the longitudinal centerline of the first gear assembly. The first-stage planetary gear includes a first gear set and a second gear set supported at the planetary gear countershaft, and the second-stage planetary gear includes a third gear set supported at a first outer portion of the planetary gear countershaft and a fourth gear set supported at a second outer portion of the planetary gear countershaft. The secondary gear assembly is positioned between the turbine and the first gear assembly, and The gear ratio of the first gear assembly ranges from 6:1 to 14:

1.

2. The turbine engine according to claim 1, characterized in that, The secondary gear assembly is a gear assembly with a rotating ring gear having a 1:1 ratio.

3. The turbine engine according to claim 1, characterized in that, The fan assembly described therein is a single-stage ductless fan blade.

4. The turbine engine according to claim 1, characterized in that, The secondary gear assembly includes a drive gear connected to the core engine, a first idler gear engaging with the drive gear, and a second idler gear engaging with the first idler gear, wherein the second idler gear is connected to an output gear that drives the output shaft of the secondary gear.

5. The turbine engine according to claim 4, characterized in that, The drive gear rotates along the first rotation direction, the first idler gear rotates along the second rotation direction, the second idler gear rotates along the first rotation direction, the output gear rotates along the second rotation direction, and the secondary gear output shaft rotates along the second rotation direction.

6. An aircraft, characterized in that, include: A first turbofan engine, the first turbofan engine having a first core engine, a first core engine output shaft rotating in a first rotational direction, a first gear assembly, and a first fan drive output shaft rotating in a second rotational direction to drive the first fan assembly to rotate in the second rotational direction; and The second turbofan engine has a second core engine, a second core engine output shaft rotating in the first rotation direction, a second gear assembly, and a second fan drive output shaft rotating in the first rotation direction to drive the second fan assembly to rotate in the first rotation direction, and a third gear assembly disposed between the second core engine and the second gear assembly and configured to reverse the rotational input of the second gear assembly. The first gear assembly receives the first core engine output shaft at a first speed and drives the first fan drive output shaft at a second speed lower than the first speed. The second gear assembly receives the second core engine output shaft at a third speed and drives the second fan drive output shaft at a fourth speed lower than the third speed; The third gear assembly receives the output shaft of the second core engine at a third speed and drives the second gear assembly at the third speed; The gear ratio of the first gear assembly ranges from 6:1 to 14:

1.

7. The aircraft according to claim 6, characterized in that, The third gear assembly is a gear assembly with a rotating ring gear having a 1:1 ratio.

8. The aircraft according to claim 6, characterized in that, The first fan assembly and the second fan assembly each include a single-stage ductless fan blade.

9. A method for reversing the rotation direction of one of a pair of fan assemblies, characterized in that, include: The first fan assembly is driven in a first rotational direction by using the input from the first core engine to the first gear assembly and the output from the first gear assembly to the first fan assembly; The second fan assembly is driven in the second rotational direction by using the input from the second core engine to the second gear assembly and the output from the second gear assembly to the second fan assembly; and By utilizing a secondary gear assembly positioned between the second core engine and the second fan assembly, the second rotation direction is reversed. The secondary gear assembly is connected to and driven by the core engine, and drives the secondary gear output shaft in a second rotational direction opposite to the first rotational direction.

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