Bearing spring for epicyclic gear system housing assembly

Abstract

A housing assembly for a epicyclic gear system includes a housing, a cylindrical gear shaft, a gear, and a bearing assembly. The housing defines a gear shaft recess having a cylindrical wall. An end portion of the cylindrical gear shaft is disposed coaxially within the gear shaft recess with the cylindrical wall. At least one gear is carried by the gear shaft. The bearing assembly includes a bearing disposed over at least a portion of the end portion of the gear shaft; and an annular spring disposed over at least a portion of the bearing.

Description

[0001] Cross-references to related applications

[0002] This application relates to the co-filed and co-pending U.S. Patent Application No. 16 / 592,492 entitled "EPICYCLICAL GEAR SYSTEM HOUSING ASSEMBLY", Attorney File No. G2640-00402 / RCA12398; U.S. Patent Application No. 16 / 592,498 entitled "STIFFENING MEMBER FOR EPICYCLICAL GEAR SYSTEM HOUSING ASSEMBLY", Attorney File No. G2640-00406 / RCA12401; and U.S. Patent Application No. 16 / 592,499 entitled "STATIC CURVIC JOINT FOR EPICYCLICAL GEAR SYSTEM HOUSING ASSEMBLY", Attorney File No. G2640-00408 / RCA12402, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to bearing springs for housing assemblies of rotary gear systems. Background Technology

[0004] Planetary gear systems are used in rotating machinery to transfer energy from one component (such as a rotating shaft) to another. By changing certain variables (such as the number, size, and number of teeth of the gears), planetary gear systems can be designed to transfer energy between components at a desired ratio, and typically convert a high-speed, low-torque input into a low-speed, higher-torque output.

[0005] Planetary gear systems are suitable for a wide range of applications, including transferring energy from a turbine shaft to the fan rotor of a geared turbine fan engine. However, in such power applications, planetary gear systems must be designed to allow a certain degree of relative motion between the parts of the system to avoid excessive wear and system failure under extreme conditions. Summary of the Invention

[0006] According to some aspects of this disclosure, a housing assembly for a planetary gear system includes a housing, a cylindrical gear shaft, at least one gear, and a bearing assembly. The housing defines a gear shaft recess having a cylindrical wall. One end of the cylindrical gear shaft is coaxially disposed within the gear shaft recess with respect to the cylindrical wall. The at least one gear is carried by a gear bearing. The bearing assembly includes a bearing disposed on at least a portion of the end of the gear shaft, and an annular spring disposed on at least a portion of the bearing.

[0007] In some embodiments, the bearing is a roller bearing. In some embodiments, two gears are carried by a gear bearing. In some embodiments, the shaft and gears form a compound star gear in a planetary gear system.

[0008] In some embodiments, the annular spring includes an annular body and a plurality of mutes spaced circumferentially around the body. In some embodiments, each of the plurality of mutes has the same radial dimension. In some embodiments, each of the plurality of mutes has a radial dimension between 0.8 and 1.0 of the radial dimension of the body. In some embodiments, each of the plurality of mutes has a radial dimension that is half the radial dimension of the body. In some embodiments, each of the plurality of mutes has a circumferential length equal to the circumferential length between adjacent mutes. In some embodiments, each of the plurality of mutes has a circumferential length between 0.8 and 1.0 of the circumferential length between adjacent mutes. In some embodiments, the circumference is an inner circumference. In some embodiments, the circumference is an outer circumference.

[0009] According to other aspects of this disclosure, a gear housing assembly in a planetary gear system includes a front housing member, a rear housing member, a planetary gear, a front bearing assembly, a rear bearing assembly, and an annular spring. The front housing member defines a plurality of gear shaft recesses having cylindrical walls. The rear housing member defines a plurality of gear shaft recesses having cylindrical walls. The planetary gear includes a cylindrical shaft having a front end portion coaxially disposed within the gear shaft recess of the front housing with respect to the cylindrical wall of the recess; a rear end portion coaxially disposed within the gear shaft recess of the rear housing member with respect to the cylindrical wall of the recess; and a pair of gears carried by bearings between the front and rear ends. The front bearing assembly includes a bearing disposed on at least a portion of the front end portion. The rear bearing assembly includes a bearing disposed on at least a portion of the rear end portion. The first annular spring is disposed on at least a portion of one of the bearings disposed on at least a portion of the front end portion and the bearing disposed on at least a portion of the rear end portion.

[0010] In some embodiments, the first gear of the gear pair engages with the sun gear, while the second gear of the gear pair engages with the ring gear. In some embodiments, the bearing assembly further includes a second ring spring disposed on at least a portion of another bearing disposed on at least a portion of the front end and at least a portion of the rear end. In some embodiments, the first and second ring springs have the same shape and size. In some embodiments, the first and second ring springs have different shapes or sizes. In some embodiments, the bearing assembly further includes an intermediate housing member defining a central bore, wherein a portion of the cylindrical shaft extends through the central bore.

[0011] According to further aspects of this disclosure, a method is proposed for relative movement between components of a planetary gear system. The method includes positioning a bearing at least partially within a recess defined by a gear housing member; bearing a portion of a cylindrical shaft carrying a planetary gear; positioning a ring spring between the bearing and the gear housing member; and bending the ring spring in response to relative movement between the bearing and the gear housing member. In some embodiments, the method further includes rotating the cylindrical shaft. Attached Figure Description

[0012] The following will be apparent from the accompanying drawings provided for illustrative purposes.

[0013] Figure 1 It is a side view cross-sectional diagram of a gas turbine engine;

[0014] Figure 2 This is a close-up cross-sectional side view of the upstream section of a gas turbine engine;

[0015] Figure 3 This is a partial cross-sectional view of a gearbox used in a gas turbine engine;

[0016] Figure 4 This is a schematic cross-sectional view of a rotary gear system according to some embodiments of the present disclosure;

[0017] Figure 5 This is a detailed schematic cross-sectional view of a planetary gear in a planetary gear system according to some embodiments of the present disclosure;

[0018] Figure 6 This is a schematic cross-sectional view of a portion of a rotary gear system according to some embodiments of the present disclosure;

[0019] Figure 7 This is a partial cross-sectional view of a spring according to some embodiments;

[0020] Figure 8 This is a flowchart of a method according to some embodiments of the present disclosure.

[0021] This application discloses exemplary (i.e., example) embodiments. The claimed invention is not limited to the illustrative embodiments. Therefore, many embodiments of the invention will differ from the illustrative embodiments. Various modifications can be made to the claimed invention without departing from the spirit and scope of this disclosure. The scope of protection of this invention is intended to cover embodiments with such modifications. Detailed Implementation

[0022] To facilitate an understanding of the principles of this disclosure, reference will now be made to several illustrative embodiments shown in the accompanying drawings, and they will be described using specific language.

[0023] As described elsewhere herein, this disclosure may relate to a gas turbine engine. Such a gas turbine engine may include an engine core comprising a turbine, a combustor, a compressor, and a core connecting the turbine to the compressor. Such a gas turbine engine may include a fan (having fan blades) located upstream of the engine core.

[0024] Although not exclusively, the arrangement of this disclosure can be particularly advantageous for fans driven via a gearbox. Thus, a gas turbine engine may include a gearbox that receives input from a spindle and outputs drive to a fan, thereby driving the fan at a lower speed than the spindle. The input to the gearbox may be directly from the spindle or indirectly from the spindle, for example, through spur gears and / or gears. The spindle may rigidly connect the turbine and the compressor such that the turbine and the compressor rotate at the same speed (the fan rotates at a lower speed).

[0025] The gas turbine engine described and / or claimed herein can have any suitable general architecture. For example, a gas turbine engine can have any desired number of shafts connecting the turbine and the compressor, such as one, two, or three shafts. By way of example only, the turbine connected to the spindle can be a first turbine, the compressor connected to the spindle can be a first compressor, and the spindle can be a first spindle. The engine core may also include a second turbine, a second compressor, and a second spindle connecting the second turbine to the second compressor. The second turbine, the second compressor, and the second spindle may be arranged to rotate at a higher rotational speed than the first spindle.

[0026] In such an arrangement, the second compressor may be located axially downstream of the first compressor. The second compressor may be arranged to receive (e.g., directly via a generally annular duct) the flow from the first compressor.

[0027] The gearbox can be arranged to be driven by a spindle configured to rotate at a minimum speed (e.g., in use) (e.g., the first spindle in the example above). For example, the gearbox can be arranged to be driven only by a spindle configured to rotate at a minimum speed (e.g., in use) (e.g., only the first spindle and not the second spindle in the example above). Alternatively, the gearbox can be arranged to be driven by any one or more shafts, such as the first and / or second shafts in the example above.

[0028] The gearbox can be a reduction gearbox (where the fan's output speed is lower than the spindle's input speed). Any type of gearbox can be used. For example, the gearbox can be a "planetary" or "star" gearbox, as described in more detail elsewhere in this document. The gearbox can have any desired reduction ratio (defined as the input shaft speed divided by the output shaft speed), for example, greater than 2.5, such as in the range of 3 to 4.2 or 3.2 to 3.8, for example, approximately or at least about 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, or 4.2. The gear ratio can, for example, be between any two values ​​in the preceding sentence. By way of example only, the gearbox can be a "star" gearbox with a ratio of 3.1 or 3.2 to 3.8. In some arrangements, the gear ratio can be outside these ranges.

[0029] In any gas turbine engine described and / or claimed herein, a combustor may be located axially downstream of the fan and compressor. For example, the combustor may be located directly downstream of a second compressor (e.g., at the outlet of the second compressor), where the second compressor is located. As a further example, the flow at the combustor outlet may be directed to the inlet of a second turbine, where the second turbine is located. The combustor may also be located upstream of the turbine.

[0030] The compressor, or each compressor (e.g., the first and second compressors as described above), may include any number of stages, such as multiple stages. Each stage may include a row of rotor blades and a row of stator blades, the stator blades being variable (in that their angle of incidence may be variable). The row of rotor blades and the row of stator blades may be axially offset from each other.

[0031] The turbine, or each turbine (e.g., the first and second turbines as described above), may include any number of stages, such as multiple stages. Each stage may include a row of rotor blades and a row of stator blades. The row of rotor blades and the row of stator blades may be axially offset from each other.

[0032] Each fan blade may be defined as having a radial span extending from the root (or hub) at a radially inner gas scrubbing position or 0% span position to the tip at a 100% span position. The ratio of the radius of the fan blade at the hub to the radius of the fan blade at the tip may be less than (or approximately) any of the following: 0.4, 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31, 0.3, 0.29, 0.28, 0.27, 0.26, or 0.25. The ratio of the radius of the fan blade at the hub to the radius of the fan blade at the tip may be within a range defined by any two values ​​in the preceding sentence (i.e., these values ​​may form an upper or lower limit), for example, in the range of 0.28 to 0.32. These ratios may generally be referred to as the hub-to-tip ratio. Both the radius at the hub and the radius at the tip can be measured at the leading edge (or the foremost part along the axial direction) of the blade. The hub-to-tip ratio refers, of course, to the gas-washing portion of the fan blade, i.e., the radially outer portion of any platform.

[0033] The fan radius can be measured between the engine centerline and the tip of the fan blades at its leading edge. The fan diameter (which may be only twice the fan radius) can be greater than (or approximately) any of the following: 220 cm, 230 cm, 240 cm, 250 cm (approximately 100 inches), 260 cm, 270 cm (approximately 105 inches), 280 cm (approximately 110 inches), 290 cm (approximately 115 inches), 300 cm (approximately 120 inches), 310 cm, 320 cm (approximately 125 inches), 330 cm (approximately 130 inches), 340 cm (approximately 135 inches), 350 cm, 360 cm (approximately 140 inches), 370 cm (approximately 145 inches), 380 cm (approximately 150 inches), 390 cm (approximately 155 inches), 400 cm, 410 cm (approximately 160 inches), or 420 cm (approximately 165 inches). The fan diameter can be within a range defined by any two values ​​in the preceding sentence (i.e., these values ​​can form an upper or lower limit), for example, in the range of 240 cm to 280 cm or 330 cm to 380 cm.

[0034] The fan speed can vary during use. Generally, for fans with larger diameters, the speed is lower. Purely by way of a non-limiting example, the fan speed under cruising conditions can be less than 2500 rpm, for example, less than 2300 rpm. Purely by way of a further non-limiting example, for an engine having a fan diameter in the range of 220 cm to 300 cm (e.g., 240 cm to 280 cm or 250 cm to 270 cm), the fan speed under cruising conditions can be in the range of 1700 rpm to 2500 rpm, for example, in the range of 1800 rpm to 2300 rpm, for example, in the range of 1900 rpm to 2100 rpm. Purely by way of a further non-limiting example, for an engine with a fan diameter in the range of 330 cm to 380 cm, the fan speed under cruising conditions can be in the range of 1200 rpm to 2000 rpm, for example, in the range of 1300 rpm to 1800 rpm, for example, in the range of 1400 rpm to 1800 rpm.

[0035] When using a gas turbine engine, a fan (with associated fan blades) rotates about a rotational axis. This rotation causes the tip of the fan blades to move at a velocity Utip. The work done by the fan blades 13 on the convection results in an enthalpy rise of dH in the flow. The load on the fan tip can be defined as dH / Utip², where dH is the enthalpy rise at the ends of the fan (e.g., a one-dimensional average enthalpy rise), and Utip is the (translational) velocity of the fan tip, for example at the leading edge of the tip (which can be defined as the fan tip radius at the leading edge multiplied by the angular velocity). The fan tip load under cruise conditions can be greater than (or approximately) any of the following: 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, or 0.4 (all units in this paragraph are J kg⁻¹ K⁻¹ / (ms⁻¹)²). The fan tip load can be within a range defined by any two values ​​in the preceding sentence (i.e., these values ​​can form an upper or lower limit), for example, in the range of 0.28 to 0.31 or 0.29 to 0.3.

[0036] The gas turbine engine according to this disclosure can have any desired bypass ratio, wherein the bypass ratio is defined as the ratio of the mass flow rate through the bypass duct to the mass flow rate through the core under cruise conditions. In some arrangements, the bypass ratio can be greater than (or approximately) any of the following: 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, or 20. The bypass ratio can be within a range encompassed by any two values ​​in the preceding sentence (e.g., these values ​​can form an upper or lower limit), for example, in the range of 12 to 16, 13 to 15, or 13 to 14. The bypass duct can be substantially annular. The bypass duct can be located radially outside the core engine. The radially outer surface of the bypass duct can be defined by the nacelle and / or fan casing.

[0037] The total pressure ratio of a gas turbine engine as described and / or claimed herein can be defined as the ratio of the stagnation pressure upstream of the fan to the stagnation pressure at the outlet of the highest-pressure compressor (before entering the combustor). By way of non-limiting example, the total pressure ratio of a gas turbine engine as described and / or claimed herein during cruise can be greater than (or approximately) any of the following: 35, 40, 45, 50, 55, 60, 65, 70, 75. The total pressure ratio can be within the range of any two values ​​in the preceding sentence (e.g., these values ​​can form an upper or lower limit), for example, in the range of 50 to 70.

[0038] The specific thrust of an engine can be defined as the net thrust of the engine divided by the total mass flow rate through the engine. Under cruise conditions, the specific thrust of the engine described and / or claimed herein may be less than (or approximately) any of the following: 110 Nkg⁻¹s, 105 Nkg⁻¹s, 100 Nkg⁻¹s, 95 Nkg⁻¹s, 90 Nkg⁻¹s, 85 Nkg⁻¹s, or 80 Nkg⁻¹s. The specific thrust may be within a range defined by any two values ​​in the preceding sentence (e.g., these values ​​may form an upper or lower limit), for example, in the range of 80 Nkg⁻¹s to 100 Nkg⁻¹s, or 85 Nkg⁻¹s to 95 Nkg⁻¹s. Such an engine may be particularly efficient compared to conventional gas turbine engines.

[0039] The gas turbine engine described and / or claimed herein may have any desired maximum thrust. By way of purely non-limiting example, the gas turbine described and / or claimed herein may be able to produce a maximum thrust of at least (or approximately) any of the following: 160 kN, 170 kN, 180 kN, 190 kN, 200 kN, 250 kN, 300 kN, 350 kN, 400 kN, 450 kN, 500 kN, or 550 kN. The maximum thrust may be within a range defined by any two values ​​in the preceding sentence (i.e., these values ​​may form an upper or lower limit). By way of example only, the gas turbine described and / or claimed herein may be able to produce a maximum thrust from 330 kN to 420 kN, for example, from 350 kN to 400 kN. The thrust mentioned above can be the maximum net thrust under standard atmospheric conditions, at sea level plus 15 degrees Celsius (ambient pressure 101.3 kPa, temperature 30 degrees Celsius) and with the engine stationary.

[0040] During operation, the flow temperature at the high-pressure turbine inlet can be particularly high. This temperature, which may be referred to as TET, can be measured at the combustion chamber outlet (e.g., immediately upstream of the first turbine blade, which may itself be referred to as the nozzle guide vane). During cruise, the TET can be at least (or approximately) any of the following: 1400K, 1450K, 1500K, 1550K, 1600K, or 1650K. The cruise TET can be within a range defined by any two values ​​in the preceding sentence (i.e., these values ​​can form an upper or lower limit). The maximum TET during engine operation can be, for example, at least (or approximately) any of the following: 1700K, 1750K, 1800K, 1850K, 1900K, 1950K, or 2000K. The maximum TET can be within a range defined by any two values ​​in the preceding sentence (i.e., these values ​​can form an upper or lower limit), for example, in the range of 1800K to 1950K. Maximum TET can occur, for example, under high thrust conditions, such as under maximum takeoff (MTO) conditions.

[0041] The fan blades and / or airfoil portions described and / or claimed herein can be made of any suitable material or combination of materials. For example, at least a portion of the fan blades and / or airfoils can be made at least partially of a composite, such as a metal matrix composite and / or an organic matrix composite, such as carbon fiber. As a further example, at least a portion of the fan blades and / or airfoils can be made at least partially of a metal, such as a titanium-based metal or an aluminum-based material (e.g., an aluminum-lithium alloy) or a steel-based material. The fan blade may include at least two regions made of different materials. For example, the fan blade may have a protective leading edge that is made of a material more resistant to impacts (e.g., birds, ice, or other materials) than the rest of the blade. Such a leading edge can be made, for example, of titanium or a titanium-based alloy. Thus, by way of example only, the fan blade may have a carbon fiber or aluminum-based body (e.g., an aluminum-lithium alloy) with a titanium leading edge.

[0042] The fan described and / or claimed herein may include a central portion from which fan blades may extend, for example, in a radial direction. The fan blades may be attached to the central portion in any desired manner. For example, each fan blade may include a retaining device that engages a corresponding slot in a hub (or disc). By way of example only, such a retaining device may be in the form of a dovetail, which may be sewn into and / or engaged in a corresponding slot in the hub / disc to secure the fan blade to the hub / disc. As a further example, the fan blades may be integrally formed with the central portion. Such an arrangement may be referred to as a blade disc or blade ring. Such a blade disc or blade ring may be manufactured using any suitable method. For example, at least a portion of the fan blades may be machined from a block, and / or at least a portion of the fan blades may be attached to the hub / disc by welding, such as linear friction welding.

[0043] The gas turbine engine described and / or claimed herein may or may not be equipped with a variable area nozzle (VAN). Such a variable area nozzle allows the outlet area of ​​the bypass duct to vary during use. The general principles of this disclosure can be applied to engines with or without a VAN.

[0044] The fan of the gas turbine described and / or claimed herein may have any desired number of fan blades, such as 14, 16, 18, 20, 22, 24 or 26 fan blades.

[0045] As used herein, cruise conditions have a conventional meaning and will be readily understood by those skilled in the art. Therefore, for a given gas turbine engine for an aircraft, those skilled in the art will immediately recognize that cruise conditions refer to the engine's operating point during mid-cruise of a given mission (referred to in the industry as an "economic mission") for which the gas turbine engine is designed to be attached. In this respect, mid-cruise refers to the point in the aircraft's flight cycle where 50% of the total fuel burned between the peak of climb and the start of descent is burned (which can be approximated in time and / or distance as the midpoint between the peak of climb and the start of descent). Thus, cruise conditions define the operating point of a gas turbine engine that provides thrust sufficient to ensure steady-state operation (i.e., maintaining a constant altitude and a constant Mach number) in mid-cruise of an aircraft to which the gas turbine engine is designed to be attached, taking into account the number of engines supplied to that aircraft. For example, in the case of an engine designed to be attached to an aircraft with two engines of the same type, under cruise conditions, the engine provides half of the total thrust required for steady-state operation of the aircraft in mid-cruise.

[0046] In other words, for a given gas turbine engine for an aircraft, cruise conditions are defined as the engine's operating point under mid-cruise atmospheric conditions (defined by the international standard atmosphere according to ISO 2533 at mid-cruise altitude) that provide (in conjunction with any other engine on the aircraft, provide the specific thrust required for the gas turbine engine to be designed for steady-state operation of the aircraft attached to it at a given mid-cruise Mach number). For any given gas turbine engine for an aircraft, the mid-cruise thrust, atmospheric conditions, and Mach number are known, and therefore the engine's operating point under cruise conditions can be clearly defined.

[0047] As an example only, the forward speed under cruise conditions can be any point in the range of Mach 0.7 to 0.9, such as 0.75 to 0.85, 0.76 to 0.84, 0.77 to 0.83, 0.78 to 0.82, 0.79 to 0.81, approximately Mach 0.8, approximately Mach 0.85, or within the range of 0.8 to 0.85. Any single speed within these ranges can be part of the cruise conditions. For some aircraft, cruise conditions may not be within these ranges, such as below Mach 0.7 or above Mach 0.9.

[0048] By way of example only, cruise conditions can correspond to standard atmospheric conditions (according to the International Standard Atmosphere, ISA) at an altitude in the range of 10,000 m to 15,000 m, for example, in the range of 10,000 m to 12,000 m, for example, in the range of 10,400 m to 11,600 m (approximately 38,000 ft), for example, in the range of 10,500 m to 11,500 m, for example, in the range of 10,600 m to 11,400 m, for example, in the range of 10,700 m (approximately 35,000 ft) to 11,300 m, for example, in the range of 10,800 m to 11,200 m, for example, in the range of 10,900 m to 11,100 m, for example, approximately 11,000 m. Cruise conditions can correspond to standard atmospheric conditions at any given altitude within these ranges.

[0049] As an example only, cruise conditions could correspond to the engine's operating point, which provides a known desired thrust level (e.g., values ​​from 30 kN to 35 kN) under standard atmospheric conditions (according to the International Standard Atmosphere) at a forward Mach number of 0.8 and an altitude of 38,000 feet (11,582 m). As a further example only, cruise conditions could correspond to the engine's operating point, which provides a known desired thrust level (e.g., values ​​from 50 kN to 65 kN) under standard atmospheric conditions (according to the International Standard Atmosphere) at a forward Mach number of 0.85 and an altitude of 35,000 feet (10,668 m).

[0050] In use, the gas turbine engines described and / or claimed herein can operate under the cruise conditions defined elsewhere herein. Such cruise conditions can be determined by the cruise conditions (e.g., medium cruise conditions) of an aircraft that can be equipped with at least one (e.g., two or four) gas turbine engines to provide propulsive thrust.

[0051] According to one aspect, an aircraft is provided that includes a gas turbine engine as described and / or claimed herein. The aircraft according to this aspect is one in which the gas turbine engine is designed to be attached. Therefore, the cruise conditions according to this aspect correspond to the mid-cruise of the aircraft, as defined elsewhere herein.

[0052] According to one aspect, a method for operating a gas turbine engine as described and / or claimed herein is provided. This operation can be performed under cruise conditions (e.g., in terms of thrust, atmospheric conditions, and Mach number) as defined elsewhere herein.

[0053] According to one aspect, a method of operating an aircraft including the gas turbine engine described and / or claimed herein is provided. Operation according to this aspect may include (or may be) operation of the aircraft at mid-cruise conditions, as defined elsewhere herein.

[0054] Figure 1 A gas turbine engine 10 with a main axis of rotation 9 is shown. Engine 10 includes an intake 12 and a propulsion fan 23 that generates two airflows: a core airflow A and a bypass airflow B. Gas turbine engine 10 includes a core 11 that receives the core airflow A. Engine core 11 includes an axial-flow series of components: a low-pressure compressor 14, a high-pressure compressor 15, a combustion device 16, a high-pressure turbine 17, a low-pressure turbine 19, and a core exhaust nozzle 20. A nacelle 21 surrounds gas turbine engine 10 and defines a bypass duct 22 and a bypass exhaust nozzle 18. Bypass airflow B flows through bypass duct 22. Fan 23 is attached to and driven by the low-pressure turbine 19 via a shaft 26 and a rotary gearbox 30.

[0055] In operation, the core airflow A is accelerated and compressed by the low-pressure compressor 14 and directed to the high-pressure compressor 15, where further compression occurs. The compressed air discharged from the high-pressure compressor 15 is directed to the combustion device 16, where it is mixed with fuel and the mixture is burned. The resulting hot combustion products then collide through the nozzle 20 to drive the expansion of the high-pressure turbine 17 and the low-pressure turbine 19 before being discharged through the nozzle 20 to provide a certain amount of propulsion. The high-pressure turbine 17 drives the high-pressure compressor 15 via a suitable interconnecting shaft 27. The fan 23 typically provides most of the propulsion. The rotary gearbox 30 is a reduction gearbox.

[0056] exist Figure 2 An exemplary arrangement for a geared fan gas turbine engine 10 is shown. Low-pressure turbine 19 (see...) Figure 1 A drive shaft 26 is connected to the sun gear or sun gear 28 of the planetary gear assembly 30. A plurality of planet gears 32 mesh radially outward from and with the sun gear 28, and are connected together by a planet carrier 34. The planet carrier 34 constrains the planet gears 32 to precess synchronously around the sun gear 28, while simultaneously causing each planet gear 32 to rotate about its own axis. The planet carrier 34 is connected to the fan 23 via a linkage 36 to drive it to rotate about the engine axis 9. A ring gear or toroidal gear 38 meshes radially outward from and with the planet gears 32, and is connected to the fixed support structure 24 via a linkage 40.

[0057] Note that the terms "low-pressure turbine" and "low-pressure compressor" as used herein may refer to the lowest pressure turbine stage and the lowest pressure compressor stage (i.e., excluding fan 23) and / or the turbine-compressor stage and compressor stage connected together via interconnecting shaft 26 at the lowest speed in the engine (i.e., excluding the gearbox output shaft driving fan 23). In some literature, the terms "low-pressure turbine" and "low-pressure compressor" as used herein may alternatively be referred to as "intermediate-pressure turbine" and "intermediate-pressure compressor." When using this alternative nomenclature, fan 23 may be referred to as the first or lowest pressure compression stage.

[0058] exist Figure 3 The rotary gearbox 30 is shown in more detail by way of example. Each of the sun gear 28, planet gear 32, and ring gear 38 includes teeth around its outer circumference for meshing with other gears. However, for clarity, in Figure 3 Only exemplary portions of the teeth are shown. Although four planetary gears 32 are shown, it will be apparent to those skilled in the art that more or fewer planetary gears 32 can be provided within the scope of the claimed invention. Practical applications of the planetary gearbox 30 typically include at least three planetary gears 32.

[0059] exist Figure 2 and Figure 3 The planetary gearbox 30 exemplarily shown is a planetary type, wherein the planet carrier 34 is coupled to the output shaft via a linkage 36, while the ring gear 38 is fixed. However, any other suitable type of planetary gearbox 30 can be used. As a further example, the planetary gearbox 30 can be a star arrangement, wherein the planet carrier 34 is held fixed, and the ring (or annular) gear 38 is allowed to rotate. In such an arrangement, the fan 23 is driven by the ring gear 38. By another alternative example, the gearbox 30 can be a differential gearbox, wherein both the ring gear 38 and the planet carrier 34 are allowed to rotate.

[0060] Will realize, Figure 2 and Figure 3 The arrangements shown are merely exemplary, and various alternatives are within the scope of this disclosure. By way of example only, any suitable arrangement can be used to position the gearbox 30 within the engine 10 and / or to connect the gearbox 30 to the engine 10. As a further example, the connection between the gearbox 30 and other parts of the engine 10 (e.g., input shaft 26, output shaft, and mounting structure 24) (e.g., in…) Figure 2The linkages 36, 40 in the examples can have any desired rigidity or flexibility. As a further example, any suitable arrangement of bearings between the rotating and stationary parts of the engine (e.g., between the input and output shafts of the gearbox and a fixed structure, such as the gearbox housing) can be used, and this disclosure is not limited to... Figure 2 Exemplary arrangements. For example, in the case where the gearbox 30 has a star arrangement (as described above), those skilled in the art will readily understand that the arrangement of the output and support linkages and the bearing positions are generally different. Figure 2 The example shown in the text.

[0061] Therefore, this disclosure extends to gas turbine engines having any arrangement of gearbox type (e.g., star or planetary), support structure, input and output shaft arrangement, and bearing location.

[0062] Optionally, the gearbox may drive additional and / or alternative components (e.g., a medium-pressure compressor and / or a booster compressor).

[0063] Other gas turbine engines to which this disclosure can be applied may have alternative configurations. For example, such engines may have alternative numbers of compressors and / or turbines and / or alternative numbers of interconnecting shafts. As a further example, Figure 1 The gas turbine engine shown has split nozzles 18 and 20, meaning that the flow through the bypass duct 22 has its own nozzle 18, which is separate from the core engine nozzle 20 and located radially outside the core engine nozzle 20. However, this is not limiting, and any aspect of this disclosure can also be applied to engines in which the flow through the bypass duct 22 and the flow through the core 11 are mixed or combined before a single nozzle (or upstream), which may be referred to as a mixing flow nozzle. One or both nozzles (whether for mixing or separating flows) may have a fixed or variable area.

[0064] The geometry of the gas turbine engine 10 and its components are defined by a conventional shaft system, which includes an axial direction (aligned with the rotating shaft 9) and a radial direction (in... Figure 1 (from bottom to top) and circumferential direction (in) Figure 1 (Vertical page in view). Axial, radial, and circumferential directions are perpendicular to each other.

[0065] Figure 4A schematic diagram of a planetary gear system 100 according to some embodiments of the present disclosure is provided. The planetary gear system 100 may be a compound planetary gear system. A sun gear 101 is coupled to and driven by a first rotatable shaft 103. The sun gear 101 meshes with one or more planetary gears 105 such that rotation of the sun gear 101 causes rotation of one or more planetary gears 105. The planetary gears 105 may be star gears, such that the planetary gears 105 rotate about an axis fixed relative to the axis of rotation of the sun gear 101.

[0066] Each of one or more planetary gears 105 meshes with a ring gear 107. The ring gear 107 is connected to a second rotatable shaft 109 via a ring gear hub 108. Thus, rotation of the first rotatable shaft 103 drives rotation of the second rotatable shaft 109 via rotation of the sun gear 101, one or more planetary gears 105, and the ring gear 107. In some embodiments, the first rotatable shaft 103 may be a turbine shaft of a turbine (i.e., a high-speed or low-speed valve core). The second rotatable shaft 109 may be a fan shaft or a fan rotor.

[0067] Figure 5 Detailed schematic diagrams of a housing assembly 111 of a planetary gear system 100 according to some embodiments of the present disclosure are provided. Each of one or more planetary gears 105 may include a cylindrical gear shaft 123, a sun gear engagement gear 125, and a ring gear engagement gear 127. The sun gear engagement gear 125 and the ring gear engagement gear 127 may be carried by the cylindrical gear shaft 123. Each of one or more planetary gears 105 is carried by the housing assembly 111. The planetary gears 105 may be compound planetary gears of the planetary gear system 100.

[0068] Housing assembly 111 may include a front housing member 113 and a rear housing member 115. In some embodiments, housing assembly 111 may further include an intermediate housing member 114. One or more of housing members 113, 114, and 115 may be combined together. The front housing member 113 and the rear housing member 115 each define a plurality of gear shaft recesses 116 having cylindrical walls 120. The intermediate housing member 114 may define a plurality of holes 116.

[0069] The cylindrical gear shaft 123 of the planetary gear 105 may have a front end portion 141 disposed within one of a plurality of gear shaft recesses 116 formed by the front housing member 113. The cylindrical gear shaft 123 of the same set of planetary gears 105 may have a rear end portion 142 disposed within one of a plurality of gear shaft recesses 116 formed by the rear housing member 115. The cylindrical gear shaft 123 may be coaxially disposed within each gear shaft recess 116 with respect to the cylindrical wall 120 of the gear shaft recess 116. The cylindrical gear shaft 123 may extend through a hole 118 defined by the intermediate housing member 114. The sun gear meshing gear 125 and the ring gear meshing gear 127 of the planetary gear 105 may be carried by the gear shaft 123 between the front end portion 141 and the rear end portion 142.

[0070] The housing assembly 111 may further include a bearing assembly 117. The housing assembly 111 may include a front bearing assembly and a rear bearing assembly. The bearing assembly 117 may include bearings. For example, a front bearing 119 may be disposed on at least a portion of the front end portion 141 of the gear shaft 123, and a rear bearing 121 may be disposed on at least a portion of the rear end portion 142 of the gear shaft 123. Each bearing 119, 121 may rotatably carry the planetary gear 105. Each bearing 119, 121 may be a roller element bearing.

[0071] During operation of the rotary gear system 100, the components of the system 100, as described above and including additional frame assemblies, housings, and bearings, may move relative to each other. Even a small change in the relative position of one component to another can have a significant impact on the performance of the system 100. For example, misalignment of meshing gear teeth and / or bearings can lead to uneven loads on the gears and / or bearings, and degrade or damage the gear teeth.

[0072] Of particular concern is the alignment of the gear shaft 123 of each planetary gear 105. Since each planetary gear 105 is carried by a gear shaft 123 partially disposed within a gear shaft recess 116 of the front housing member 113, any relative movement or change in relative position between the front housing member 115 and the rear housing member 115 can cause misalignment of the planetary gear 105. Similarly, any relative movement or change in relative position between the intermediate housing member 114 and between the front housing member 113 and the rear housing member 115 can also cause misalignment of the planetary gear 105.

[0073] This misalignment can lead to uneven load distribution among the planetary gears 105, gear degradation, and a shortened service life of the planetary gears 105 and / or planetary bearings. Factors that can cause planetary gear misalignment include misalignment forces between the front bearing 119 and the rear bearing 121, inaccurate manufacturing of the gear shaft recess 116 and the hole 118, gear tolerances, and the inflexibility and / or relative stiffness between each housing component 113, 114, 115.

[0074] Therefore, this disclosure relates to systems and methods for improving and maintaining planetary gear alignment in a planetary gear system. More specifically, this disclosure relates to a housing assembly for a planetary gear system, the housing assembly having a housing, a gear carried by a gear bearing, a bearing carrying a portion of a gear shaft, and a ring spring. The ring spring is disposed between the bearing and the housing (i.e., one of the front housing member or the rear housing member) to accommodate relative movement between the two.

[0075] Figure 6 A schematic cross-sectional view of a portion of a rotary gear system 100 according to some embodiments of the present disclosure is provided. Figure 6 The cross-section shown is normal to the rotation axis of the first axis 103 and / or the second axis 109, while Figure 4 and 5 The cross-section shown is taken along the axis of rotation. Although it is marked... Figure 6 The front housing member 113 is shown, but the same applies to the rear housing member 115 and / or the intermediate housing member 114.

[0076] like Figure 6 As shown, the bearing assembly 117 may include an annular spring 131 disposed on at least a portion of the bearing 119. The spring 131 may be positioned between the bearing 119 and the front housing member 113. The spring 131 may be at least partially positioned within a gear shaft recess 116 between the front housing member 113 and the bearing 119. The spring 131 may be coaxial with one or both of the cylindrical wall 120 of the gear shaft recess 116 and the bearing 119. The spring 131 is accommodating relative movement between the front housing member 113 and the bearing 119. The spring 131 effectively prevents, reduces, or minimizes misalignment of the gear shaft 123.

[0077] Spring 131 can be adjusted to achieve the desired deflection and / or stiffness. Figure 7 A partial cross-sectional view of a spring according to some embodiments is provided. The spring 131 may include an annular body 133 and a plurality of mufflers 135 spaced apart around one or both of the inner and outer circumferences of the annular body 133. The shape, dimensions (e.g., radial depth, circumferential length, etc.) and spacing of the mufflers 135 may be varied to achieve a desired deflection and / or stiffness of the spring 131, thereby achieving a desired or possible reduction of the front-to-back misalignment of the gear shaft 123.

[0078] exist Figure 7 In one embodiment, the spring 131 includes a plurality of mufflers 135 spaced apart around the inner and outer circumferences of the annular body 133. The mufflers 135 are shaped to have linear side edge surfaces 136 and arcuate radial outer surfaces 137. In other embodiments, the mufflers 135 may be shaped as arcuate, parabolic, curved, or linear.

[0079] exist Figure 7 In one embodiment, the radial dimension D2 of the muffler 135 along its outer circumference is approximately half the radial dimension D1 of the body 133. In other embodiments, the radial dimension D2 of the muffler 135 along its outer circumference may be between 0.25 and 1.25 of the radial dimension D1 of the body 133. The radial dimension D3 of the muffler 135 along its inner circumference is approximately half the radial dimension D1 of the body 133. In other embodiments, the radial dimension D3 of the muffler 135 along its inner circumference may be between 0.25 and 1.25 of the radial dimension D1 of the body 133. All mufflers 135 along their outer or inner circumference may have the same radial dimensions D2 and D3 as other mufflers 135 along the same circumference. However, in some embodiments, the muffler 135 may have varying radial dimensions D2 and D3 compared to other mufflers 135 along the same circumference of the body 133. In some embodiments, the muffler 135 along the inner and / or outer circumference may have radial dimensions D2, D3 between 0.8 and 1.0 of the radial dimension D1 of the body 133.

[0080] exist Figure 7 In one embodiment, the muffler 135 has a circumferential length L1 along its outer circumference, which is approximately equal to the circumferential length L2 between the mufflers 135. In other words, the mufflers 135 are spaced apart from each other by a distance L2 equal to the length L1 of the mufflers 135. In other embodiments, the mufflers 135 may have a circumferential length L1 along their outer circumference that is between 0.25 and 1.25 of the circumferential length L2 to separate adjacent mufflers 135. Similarly, the mufflers 135 along their inner circumference have a circumferential length L3 that is approximately equal to the circumferential length L4 between the mufflers 135. In other embodiments, the mufflers 135 may have a circumferential length L3 along their inner circumference that is between 0.25 and 1.25 of the circumferential length L4 to separate adjacent mufflers 135. In some embodiments, the muffler 135 along the inner circumference and / or outer circumference may have circumferential lengths L1 and L3 between 0.8 and 1.0 of the circumferential lengths L2 and L4 between the mufflers 135.

[0081] The radial dimension D1 of spring 131 can be determined to achieve the desired stiffness and / or deflection of spring 131. The radial dimension D1 of spring 131 can be uniform or non-uniform about the circumference of spring 131. The radial dimension D1 of the first (e.g., front) spring 131 can be different from or the same as the radial dimension D1 of the second (e.g., rear) spring 131.

[0082] The number of mufflers 135 spaced apart around the inner and / or outer circumference of the spring 131 can also be varied to achieve the desired stiffness and / or deflection of the spring 131. The mufflers 135 can be spaced evenly or unevenly around the circumference. The number of mufflers 135 of the first (e.g., front) spring 131 can be different from or the same as the number of mufflers 135 of the second (e.g., rear) spring 131.

[0083] In some embodiments, one or more housing bushings (not shown) may be located in the gear shaft recess 116. The housing bushings may be located between the spring 131 and the front housing member 113, and / or may be located between the spring 131 and the bearing 119.

[0084] In some embodiments, spring 131 may be disposed on at least a portion of one of bearings 119 or 121. In other words, spring 131 may be positioned between only one of the front bearing 119 and the front housing member 113 or the rear roller element bearing 121 and the rear housing member 115. For example, to achieve a desired deflection of gear shaft 123, embodiments may include spring 131 positioned between the rear roller element bearing 121 and the rear housing member 115, without spring 131 positioned between the front bearing 119 and the front housing member 113.

[0085] In some embodiments, the shape, size, and noise level of the spring 131 located between the front bearing 119 and the front housing member 113 may differ from that of the spring 131 located between the rear roller element bearing 121 and the rear housing member 115. In some embodiments, the spring 131 located between the front bearing 119 and the front housing member 113 may have a first stiffness, and the spring 131 located between the rear roller element bearing 121 and the rear housing member 115 may have a second stiffness. The first stiffness may be greater than, equal to, or less than the second stiffness.

[0086] During operation of the planetary gear system 100, a force from the bearing 119 is applied to the spring 131, causing the spring 131 to deflect partially until it contacts the housing member 113. The spring 131 allows the portion of the gear shaft 123 that is loaded more than other portions to deflect gradually more than other portions, thus, within the constraints of the spring stiffness, the load across the multiple gear shafts 123 of the planetary gear system 100 is evenly distributed.

[0087] Figure 8 This is a flowchart of a method 500 for adapting relative motion between components of a rotary gear system 100 according to some embodiments of the present disclosure. Method 500 begins at block 501. It can be described as follows: Figure 8 The steps of method 500 presented in boxes 501 to 513 may be executed in the order presented or another order. One or more steps of method 500 may not be executed.

[0088] At frame 503, bearing 119 may be at least partially positioned in a gear shaft recess 116 defined by housing member 113 of planetary gear system 100. At frame 505, bearing 119 may carry at least a portion of gear shaft 123 of planetary gear 105 of planetary gear system 100. Bearing 119 may be disposed on at least a portion of end 141 of gear shaft 123.

[0089] At frame 507, the annular spring 131 can be at least partially positioned in the gear shaft recess 116. The annular spring 131 can be positioned between the bearing 119 and the planetary gear housing member 113. The annular spring 131 can be disposed on a portion of the bearing 119. The annular spring 131 can be substantially as referenced above. Figure 6 and 7 As stated above.

[0090] At frame 509, gear shaft 123 can be rotated, for example, by the rotation of sun gear 101 or ring gear 107 that engages with planetary gear 105. Rotation of gear shaft 123 and / or operation of the planetary gear system 100 may cause gear shaft 123 to deflect and / or misalignment of gear shaft 123.

[0091] At frame 511, the annular spring 131 can bend or deflect in response to the relative movement between the bearing 119 and the planetary gear housing member 113. The bending or deflection of the annular spring 131 can accommodate all or some of the relative movement between the bearing 119 and the planetary gear housing member 113.

[0092] Method 500 ends at box 513.

[0093] The currently disclosed planetary gear system 100, housing assembly 111, and bearing assembly 117 offer numerous advantages over prior art systems. Since bearing life is proportional to the cube of the bearing load, the disclosed spring-equipped bearing assembly significantly improves bearing life by ensuring a more uniform load distribution. The disclosed spring can adapt to the deflection of the planetary gear shaft to improve load distribution, and the spring can be customized to achieve the desired impact for the front-to-back alignment of the planetary gear shaft.

[0094] Although examples have been shown and described herein, the embodiments are not limited to the details shown, as various modifications and structural changes can be made therein within the scope and range of the equivalents of the claims by those skilled in the art.

Claims

1. A housing assembly for a planetary gear system in a gas turbine engine, comprising: The housing defines a gear shaft recess with a cylindrical wall; Planetary gears, comprising: A cylindrical gear shaft, one end of which is coaxially disposed within the recess of the gear shaft with the cylindrical wall; The sun gear meshing gear is supported by a cylindrical gear bearing; and Ring gear meshing gear supported by cylindrical gear bearings; The sun gear that meshes with the planetary gears; Ring gears that mesh with planetary gears; and Bearing assembly, including: A bearing, disposed on at least a portion of the end of the gear shaft; and A ring spring is disposed on at least a portion of the bearing. The cylindrical gear shaft, sun gear, planetary gear, and ring gear form a compound star gear in the planetary gear system.

2. The housing assembly according to claim 1, wherein, The bearing is a roller bearing.

3. The housing assembly according to claim 1, wherein, The sun gear meshes with the sun gear meshing gear, and the ring gear meshes with the ring gear meshing gear.

4. The housing assembly according to claim 1, wherein, The annular spring includes an annular body and a plurality of silencers spaced apart around the circumference of the body.

5. The housing assembly according to claim 4, wherein, Each of the plurality of silencers has the same radial dimension.

6. The housing assembly according to claim 5, wherein, Each of the plurality of mufflers has a radial dimension between 0.8 and 1.0 of the radial dimension of the body.

7. The housing assembly according to claim 5, wherein, Each of the plurality of silencers has a radial dimension that is half the radial dimension of the body.

8. The housing assembly according to claim 4, wherein, Each of the plurality of mufflers has a circumferential length equal to the circumferential length between adjacent mufflers.

9. The housing assembly according to claim 4, wherein, Each of the plurality of mufflers has a circumferential length between 0.8 and 1.0 in the circumferential length between adjacent mufflers.

10. The housing assembly according to claim 4, wherein, The circumference is the inner circumference.

11. The housing assembly according to claim 4, wherein, The circumference referred to is the outer circumference.

12. A method for adapting relative motion between components of a planetary gear system in a gas turbine engine, the method comprising: The bearing is positioned at least partially in a recess defined by the gear housing member of the housing assembly as described in any one of claims 1-11; A portion of the cylindrical shaft that carries the planetary gears is used in the bearing; The annular spring is positioned between the bearing and the gear housing component; and The annular spring bends in response to the relative movement between the bearing and the gear housing components.

13. The method of claim 12, further comprising rotating the cylindrical shaft.

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