DE102020122418A1 - Planetary gear - Google Patents

Abstract

The invention relates to a planetary gearbox which has a sun gear (28), a plurality of planetary gears (32), a ring gear (38) and a plurality of planetary pins (6), one planetary pin (6) being arranged in each planetary gear (32) is and the planet pin (6) and the planet gear (32) form a bearing (7). It is provided that the planetary pin (6) forms a main body (61) and a bearing ring (62) which is radially spaced from the main body (61) and which forms the bearing (7) with the planetary gear (32). The main body (61) and the bearing ring (62) are connected to one another via at least one radially extending web (63), at least one recess (41, 42) is provided, which extends from the axially front end (601) or from the axially rear end (602) of the planetary pin (6) between the main body (61) and the bearing ring (62) as far as the at least one web (63), and in the case of two recesses (41, 42) these are asymmetrical with respect to the axial center (M) of the planet pin (6) formed in the planet pin (6).

Description

The invention relates to a planetary gear set according to the preamble of claim 1.

It is known to couple the fan of a geared turbofan engine to a turbine shaft via a planetary gear, the planetary gear receiving an input from the turbine shaft and providing drive for the fan to drive the fan at a lower speed than the turbine shaft. The planetary gear includes planetary gears which are driven by a sun gear and which rotate in a ring gear. A planetary pin is arranged in each of the planetary gears, the axial ends of the planetary pins being fastened to an axially front and axially rear carrier plate of a planet carrier. The planet carrier is coupled to a drive for the fan. Such a planetary gear is for example from DE 10 2017 127 876 A1 known.

The planetary gears in geared turbofan engines are exposed to very high centrifugal forces and torques, which deform the planetary pin and the planetary gear and can influence the lubricating film in the sliding bearing between these two elements, thereby impairing the functionality of the sliding bearing. In particular, there is a risk that the sliding bearing gap between the planetary pin and the planetary gear will be deformed and no longer have a constant thickness.

There is therefore a need to optimize the properties of the sliding bearing between the planetary pin and the planetary gear so that the sliding bearing gap runs as straight as possible in the axial direction despite the loads that occur. This also applies in the event that the bearing between the planet pin and the planet gear is designed as a roller bearing.

From the US 2016/0201793 A1 it is known to make axial undercuts on a planetary pin of a planetary gear, which are symmetrical.

The invention is based on the object of providing a planetary gear with planetary gears and planetary pins which enables the bearing gap between the planetary pin and the planetary gear to be formed effectively.

This object is achieved by a planetary gear with the features of claim 1. Refinements of the invention are given in the dependent claims.

According to the present invention, a planetary gear set has a sun gear that rotates about an axis of rotation of the planetary gear and can be driven by a sun shaft, the axis of rotation defining an axial direction of the planetary gear. A plurality of planet gears are provided, which are driven by the sun gear, and a ring gear with which the plurality of planet gears are in mesh. The planetary gear further comprises a plurality of planetary pins, one planetary pin each being arranged in a planetary gear and the planetary pin and the planetary gear forming a bearing.

It is provided that the planetary pin forms a main body and a bearing ring which is radially spaced from the main body and which forms the bearing with the planetary gear, the main body and the bearing ring being connected to one another via at least one radially extending web, at least one recess is provided which extends from the axially front end or from the axially rear end of the planet pin between the main body and the bearing ring to the at least one web, and in the case of several recesses, these are formed asymmetrically with respect to the axial center of the planet pin in the planet pin.

The fact that the several recesses are designed asymmetrically in relation to the axial center of the planetary pin in the planetary pin means that when one recess is mirrored on a straight line that runs through the axial center of the planetary pin and runs perpendicular to the axial direction, it does not go into the other recess is transferred identically. An asymmetry is therefore particularly present when the two recesses extend over a different length in the axial direction and / or have a different shape in longitudinal section, so that one recess cannot be transferred into the other recess by mirroring.

It should be noted that in the event that only one recess is provided, this is also designed asymmetrically with respect to the axial center of the planetary pin, as it cannot run symmetrically to the axial center of the planetary pin. This is due to the fact that it extends from one of the axial end faces in the planetary pin, but does not form a continuous annular gap or annular channel, since the main body and the bearing ring are connected to one another by at least one web.

The invention is based on the idea of improving the axial rigidity of the planetary pin when the force acts on the pin asymmetrically by designing the planetary pin with one or more asymmetrically designed recesses between the main body and the bearing ring. Because of the recesses radially below the axial ends of the bearing ring, the bearing ring can be more easily deformed at its axial ends during operation, so that under load the planet pin clings better to the planet gear and a uniform bearing gap with parallel contact surfaces is created over the axial length of the bearing can. As a result, the lubricating film of the slide bearing exhibits smaller changes in thickness over the axial length.

Due to the asymmetrical design of the space radially below the bearing ring by means of the asymmetrical recesses provided according to the invention, the axial stiffness distribution of the sliding bearing ring can be optimized in order to compensate for disadvantageous deformations and to improve the general bearing functionality and performance.

Via the axial position of the web, the axial area of greatest rigidity of the planetary pin can be provided at an axial position at which the bearing forces and / or asymmetries of the load are greatest. Detrimental deflections can be minimized and the lubricating film performance of the bearing can be optimized via the axial length and / or geometry of the recesses and the axial position of the web. Furthermore, an eccentric web enables any misalignment of the planetary gear and / or the planetary pin to be decoupled from the alignment of the contact surfaces of the bearings with one another.

For the background of the invention, it is pointed out that optimum bearing performance is provided by a gap that is parallel in the axial direction between the planetary gear and the planetary pin. Any local deflection and / or misalignment of the planetary gear and / or the planetary pin leads to a distorted gap function, i.e. a non-parallel course in the axial direction and thus endangers the performance of the bearing. If the gap between the planetary gear and the bearing ring of the planetary pin (also known as the gap function) is not optimally set for the power density of the epicyclic gearbox for aircraft engines, this can even lead to the oil lubricating film in this gap collapsing, causing the planetary gear and the planetary pin to come into contact and solid body friction arises between them, which in turn wear out the components and thus premature failure of the components and the entire system can occur.

The bearing ring forms an outer surface or outer circumferential surface which forms the bearing surface of the planetary pin, which forms a bearing with the inner surface of a bore formed in the planetary gear. The bearing between the planetary pin and the planetary gear can be a plain bearing or a roller bearing. If the bearing is a plain bearing, the bearing ring is a plain bearing ring.

In principle, it is sufficient that only one web is provided, which extends between the main body and the bearing ring. However, embodiments provide that several webs are provided which are axially spaced apart. A recess existing between two such webs can be used, for example, to supply oil to the bearing gap.

One embodiment of the invention provides that the main body is cylindrical. However, this is not necessarily the case. For example, it can be provided in alternative configurations that the main body has a changing diameter in the circumferential direction, that is to say is rotationally asymmetrical. It can also be provided in configurations that the wall thickness of the main body changes in the axial direction, for example in configurations in which the radial height of at least one of the recesses varies in the axial direction.

Another embodiment of the invention provides that the main body has a continuous axial bore, in particular is designed as a hollow cylinder. Oil for the lubricating film of the bearing between the planetary pin and the planetary gear, for example, is provided via the axial bore.

A further embodiment of the invention provides that the at least one web, which connects the main body and the bearing ring, is arranged eccentrically. However, this is not necessarily the case if there is already an asymmetry due to a different geometry of the two recesses.

As already noted, one embodiment of the invention provides that the planetary pin has exactly two recesses, each of which extends from one of the ends of the planetary pin. An asymmetry can be provided that the two recesses have a different axial length and / or that the two recesses have a different radial height and / or that the two recesses have a different geometry or shape in longitudinal section in a different way.

For example, it can be provided that the radial height of at least one of the recesses decreases with increasing distance from the corresponding end of the planetary pin, the recess thus tapering in the direction of the web. Such tapering can occur in the two Recesses take place to different degrees or only be implemented in one of the recesses.

Another embodiment provides that at least one of the recesses is essentially rectangular in shape in the longitudinal section. The feature “essentially” rectangular is to be understood to the effect that the recess in the transition to the web does not necessarily have to be rectangular in the sectional view.

According to a further embodiment, the planetary pin has only one axial recess, the radially extending web for this case being arranged on one of the axial ends of the planetary pin.

Refinements of the invention provide that the ratio of the axial length of the bearing ring to the axial length of the web (or the summed total axial length of the webs, if several webs are present) is in the range between 1.3 and 30. This ratio naturally also determines the ratio of the total axial length of the recesses to the axial length of the web. The axial length of the web is referred to as the axial length of the web that it has in the radial center between the outer surface of the main body and the inner surface of the bearing ring, that is, halfway between the main body and the bearing ring.

Another embodiment of the invention provides that the bearing ring has a smaller axial length than the main body. If the planet pin is attached at its axially front end to an axially front carrier plate and at its axially rear end to an axially rear carrier plate of the planetary gear, which is the case in embodiments of the invention, only the main body is at its axial ends with the front and connected to the rear support plate, while the bearing ring is not connected to the front and rear support plates.

This configuration makes it possible to provide a planet pin with an outer diameter that is larger than the diameter of the fastening openings for the planet pin in the carrier plate, and at the same time to maintain a high rigidity of the carrier plates by only attaching the main body with the smaller outer diameter to the carrier plates . Accordingly, the fastening openings formed in the carrier plates can be provided with a correspondingly smaller diameter. This in turn makes it possible to make the carrier plates thinner and thereby save weight while maintaining the same rigidity. For example, the front support plate and the rear support plate are designed as separate parts, i.e. H. there is a multi-piece planet carrier.

Another embodiment of the invention provides that the web has concave side walls (namely a concave axially front side wall and a concave axially rear side wall) that are smooth, without the formation of edges, in a radially outer boundary and in a radially ignore the inner boundary of the respective recess. Alternatively, the web can for example have side walls extending in a straight line in the radial direction, in which case the radially outer delimitation and the radially inner delimitation of the respective recess extend axially perpendicular to the respective side wall. However, in such a case it is advantageous to round the corners in order to avoid stress concentrations in them.

According to one embodiment variant, the at least one recess extends over 360 ° in the circumferential direction of the planetary pin. The planetary pin is designed as a body of revolution, d. H. it is rotationally symmetrical with respect to its longitudinal axis. However, this is not necessarily the case. Alternative design variants provide that the at least one recess extends only over a circumferential area smaller than 360 °. The recess or the recesses therefore do not extend over the entire circumference of the planetary pin, but rather only over a defined angular range in the circumferential direction. It can also be provided that the circumferential angle over which the at least one recess extends in the circumferential direction varies in the axial direction. It can also be provided that only one of the cutouts extends over a circumferential area smaller than 360 °, while the other cutout extends over 360 ° in the circumferential direction.

The main body, the at least one web and the bearing ring are firmly connected to one another and, according to an advantageous embodiment, are made in one piece. In principle, however, the main body and the bearing ring can also consist of separate parts that are non-rotatably connected to one another, the web being connected either to the main body or to the bearing ring.

• - einen Triebwerkskern, der eine Turbine, einen Verdichter und eine die Turbine mit dem Verdichter verbindende, als Hohlwelle ausgebildete Turbinenwelle umfasst;
• - einen Fan, der stromaufwärts des Triebwerkskerns positioniert ist, wobei der Fan mehrere Fanschaufeln umfasst und durch eine Fanwelle angetrieben wird; und
• - ein Planetengetriebe gemäß Anspruch 1, dessen Eingang mit der Turbinenwelle und dessen Ausgang mit der Fanwelle verbunden ist.

The invention also relates to a gas turbine engine for an aircraft, comprising:

• an engine core which comprises a turbine, a compressor and a turbine shaft designed as a hollow shaft and connecting the turbine to the compressor;
• a fan positioned upstream of the engine core, the fan having a plurality of Comprises fan blades and is driven by a fan shaft; and
• - A planetary gear according to claim 1, the input of which is connected to the turbine shaft and the output of which is connected to the fan shaft.

• - die Turbine eine erste Turbine ist, der Verdichter ein erster Verdichter ist und die Turbinenwelle eine erste Turbinenwelle ist;
• - der Triebwerkskern ferner eine zweite Turbine, einen zweiten Verdichter und eine zweite Turbinenwelle, die die zweite Turbine mit dem zweiten Verdichter verbindet, umfasst; und
• - die zweite Turbine, der zweite Verdichter und die zweite Turbinenwelle dahingehend angeordnet sind, sich mit einer höheren Drehzahl als die erste Turbinenwelle zu drehen.

A configuration for this can provide that

• the turbine is a first turbine, the compressor is a first compressor and the turbine shaft is a first turbine shaft;
• the engine core further comprises a second turbine, a second compressor and a second turbine shaft connecting the second turbine to the second compressor; and
• the second turbine, the second compressor and the second turbine shaft are arranged to rotate at a higher speed than the first turbine shaft.

It should be noted that the present invention is described with reference to a cylindrical coordinate system which has the coordinates x, r and φ. Here x indicates the axial direction, r the radial direction and φ the angle in the circumferential direction. The axial direction is identical to the machine axis of the gas turbine engine in which the planetary gear is contained, the axial direction pointing from the engine inlet in the direction of the engine outlet. Starting from the x-axis, the radial direction points radially outwards. Terms such as “in front”, “behind”, “front” and “rear” relate to the axial direction or the direction of flow in the engine. Terms like “outer” or “inner” refer to the radial direction.

As noted elsewhere herein, the present disclosure may relate to a gas turbine engine. Such a gas turbine engine may include an engine core that includes a turbine, a combustion chamber, a compressor, and a core shaft connecting the turbine to the compressor. Such a gas turbine engine may include a fan (with fan blades) positioned upstream of the engine core.

Arrangements of the present disclosure may be particularly, but not exclusively, advantageous for fans that are driven via a transmission. Accordingly, the gas turbine engine may include a transmission that receives input from the core shaft and provides drive for the fan to drive the fan at a lower speed than the core shaft. The input for the transmission can take place directly from the core shaft or indirectly from the core shaft, for example via a spur shaft and / or a spur gear. The core shaft may be rigidly connected to the turbine and the compressor so that the turbine and the compressor rotate at the same speed (with the fan rotating at a lower speed).

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

With such an arrangement, the second compressor can be positioned axially downstream of the first compressor. The second compressor may be arranged to receive flow from the first compressor (e.g., receive directly, e.g., via a generally annular channel).

The gearbox may be arranged to be driven by the core shaft configured to rotate (e.g. in use) at the lowest speed (e.g. the first core shaft in the example above). For example, the transmission can be arranged to be driven only by the core shaft which is configured to rotate (e.g. in use) at the lowest speed (e.g. only by the first core shaft and not the second core shaft in the above example) will. Alternatively, the transmission can be arranged to be driven by one or more shafts, for example the first and / or the second shaft in the above example.

In a gas turbine engine described and / or claimed here, a combustion chamber may be provided axially downstream of the fan and the compressor (s). For example, the combustion chamber can be located directly downstream of the second compressor (for example at its outlet) if a second compressor is provided. As a further example, the flow at the outlet of the compressor can be fed to the inlet of the second turbine if a second turbine is provided. The combustion chamber can upstream of the turbine (s).

The or each compressor (for example the first compressor and the second compressor as described above) can comprise any number of stages, for example a plurality of stages. Each stage can include a series of rotor blades and a series of stator blades, which can be variable stator blades (in that their angle of attack can be variable). The row of rotor blades and the row of stator blades can be axially offset from one another.

The or each turbine (for example the first turbine and the second turbine as described above) can comprise any number of stages, for example multiple stages. Each stage can include a number of rotor blades and a number of stator blades. The row of rotor blades and the row of stator blades can be axially offset from one another.

Each fan blade may be defined with a radial span extending from a root (or hub) at a radially inward gas overflow location or at a 0% span position to a 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 on the order of): 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 can be in an inclusive range bounded by two of the values in the preceding sentence (i.e., the values can be upper or lower limits). These ratios can generally be referred to as the hub-to-tip ratio. The radius at the hub and the radius at the tip can both be measured at the leading edge portion (or the axially most forward edge) of the blade. The hub-to-tip ratio, of course, relates to the portion of the fan blade overflowing with gas; H. the portion that is radially outside of any platform.

The radius of the fan can be measured between the centerline of the engine and the tip of the fan blade at its forward edge. The diameter of the fan (which can be simply twice the radius of the fan) can be greater than (or on the order of): 250 cm (about 100 inches), 260 cm, 270 cm (about 105 inches), 280 cm (about 110 inches), 290 cm (about 115 inches), 300 cm (about 120 inches), 310 cm, 320 cm (about 125 inches), 330 cm (about 130 inches), 340 cm (about 135 inches), 350 cm, 360 cm (about 140 inches), 370 cm (about 145 inches), 380 cm (about 150 inches), or 390 cm (about 155 inches). The fan diameter can be in an inclusive range bounded by two of the values in the preceding sentence (i.e., the values can be upper or lower limits).

The speed of the fan can vary with use. In general, the speed is lower for fans with a larger diameter. By way of non-limiting example only, the speed of the fan under constant speed conditions may be less than 2500 rpm, for example less than 2300 rpm. Merely as a further non-limiting example, the speed of the fan under constant speed conditions for an engine with a fan diameter in the range from 250 cm to 300 cm (for example 250 cm to 280 cm) in the range from 1700 rpm to 2500 rpm, for example in the range from 1800 rpm to 2300 rpm, for example in the range from 1900 rpm to 2100 rpm. Merely as a further non-limiting example, the speed of the fan under constant speed conditions for an engine with a fan diameter in the range from 320 cm to 380 cm in the range from 1200 rpm to 2000 rpm, for example in the range from 1300 rpm min to 1800 rpm, for example in the range from 1400 rpm to 1600 rpm.

In use of the gas turbine engine, the fan (with associated fan blades) rotates about an axis of rotation. This rotation causes the tip of the fan blade to move _{at a speed U tip.} The work done by the fan blades on the flow results in an increase in the enthalpy dH of the flow. _{A fan peak} load can be defined as dH / U ^{peak 2} , where dH is the enthalpy increase (e.g. the average 1-D enthalpy increase) across the fan and U _{peak is} the (translational) speed of the fan tip, e.g. at the front edge of the tip , (which can be defined as the fan tip radius at the front edge multiplied by the angular velocity). The fan peak load at constant speed conditions can be more than (or on the order of): 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38 , 0.39 or 0.4 (where all units in this section are Jkg ^-1 K ^-1 / (ms ^-1 ) ² ). The fan peak load can be in an inclusive range bounded by two of the values in the preceding sentence (ie, the values can be upper or lower limits).

Gas turbine engines in accordance with the present disclosure may have any desired bypass ratio, the bypass ratio being defined as the ratio of the mass flow rate of the flow through the bypass duct to the mass flow rate of the flow through the core at constant velocity conditions. In some arrangements, the bypass ratio can be more than (on the order of): 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5 , 16, 16.5 or 17 are (lie). The bypass ratio can be in an inclusive range bounded by two of the values in the preceding sentence (ie the values can form upper or lower limits). The bypass channel can be essentially ring-shaped. The bypass duct can be located radially outside the engine core. The radially outer surface of the bypass duct can be defined by an engine nacelle and / or a fan housing.

The total pressure ratio of a gas turbine engine described and / or claimed herein can be defined as the ratio of the back pressure upstream of the fan to the back pressure at the outlet of the super high pressure compressor (before the inlet to the combustion chamber). As a non-limiting example, the total pressure ratio of a gas turbine engine described and / or claimed herein at constant speed may be greater than (or on the order of): 35, 40, 45, 50, 55, 60, 65, 70, 75 (lie). The total pressure ratio can be in an inclusive range bounded by two of the values in the preceding sentence (i.e., the values can be upper or lower limits).

The specific thrust of an engine can be defined as the net thrust of the engine divided by the total mass flow through the engine. Under constant speed conditions, the specific thrust of an engine described and / or claimed here can be less than (or in the order of magnitude of): 110 Nkg ^-1 s, 105 Nkg ^-1 s, 100 Nkg ^-1 s, 95 Nkg ^-1 s, 90 Nkg ^-1 s, 85 Nkg ^-1 s or 80 Nkg ^-1 s. The specific thrust can lie in an inclusive range which is limited by two of the values in the preceding sentence (ie the values can form upper or lower limits). Such engines can be particularly efficient compared to conventional gas turbine engines.

A gas turbine engine described and / or claimed herein can have any maximum thrust desired. As a non-limiting example only, a gas turbine described and / or claimed here can be used to generate a maximum thrust of at least (or on the order of): 160kN, 170kN, 180kN, 190kN, 200kN, 250kN, 300kN, 350kN, 400kN , 450kN, 500kN or 550kN. The maximum thrust can be in an inclusive range bounded by two of the values in the preceding sentence (ie the values can be upper or lower limits). The thrust referred to above may be the maximum net thrust under standard atmospheric conditions at sea level plus 15 degrees C. (Ambient pressure 101.3 kPa, temperature 30 degrees C. ) be with a static engine.

In use, the temperature of the flow at the inlet of the high pressure turbine can be particularly high. This temperature, which can be referred to as TET, can be measured at the exit to the combustion chamber, for example immediately upstream of the first turbine blade, which in turn can be referred to as a nozzle guide vane. At constant speed, the TET can be at least (or on the order of): 1400K, 1450K, 1500K, 1550K, 1600K or 1650K. The TET at constant speed can be in an inclusive range bounded by two of the values in the preceding sentence (i.e., the values can be upper or lower limits). The maximum TET when the engine is in use can, for example, be at least (or on the order of): 1700K, 1750K, 1800K, 1850K, 1900K, 1950K or 2000K. The maximum TET can be in an inclusive range bounded by two of the values in the preceding sentence (i.e. the values can be upper or lower limits). The maximum TET can occur, for example, in a condition of high thrust, for example in an MTO condition (MTO - maximum take-off thrust - maximum take-off thrust).

A fan blade and / or a blade portion of a fan blade described and / or claimed herein can be made from any suitable material or combination of materials. For example, at least a portion of the fan blade and / or the blade can be made at least in part from a composite, for example a metal matrix composite and / or a composite with an organic matrix, such as e.g. B. carbon fiber. As another example, at least a portion of the fan blade and / or the blade can be at least in part made of a metal, such as metal. A titanium-based metal or an aluminum-based material (such as an aluminum-lithium alloy) or a steel-based material. The fan blade can include at least two sections made using different materials. For example, the fan blade can have a front protective edge made using a material that can withstand impact (such as birds, ice, or other material) better than the rest of the shovel. Such a leading edge can be manufactured using titanium or a titanium-based alloy, for example. Thus, by way of example only, the fan blade may comprise a carbon fiber or aluminum based body (such as an aluminum-lithium alloy) with a leading edge made of titanium.

A fan described and / or claimed herein may include a central portion from which the fan blades may extend, for example in a radial direction. The fan blades can be attached to the central section in any desired manner. For example, each fan blade can include a fixation device that can engage a corresponding slot in the hub (or disc). Merely as an example, such a fixing device can be in the form of a dovetail which can be inserted into a corresponding slot in the hub / disc and / or brought into engagement therewith in order to fix the fan blade to the hub / disc. As another example, the fan blades can be formed integrally with a central portion. Such an arrangement can be referred to as a blisk or a bling. Any suitable method can be used to manufacture such a blisk or bling. For example, at least a portion of the fan blades can be machined from a block and / or at least a portion of the fan blades can be welded, e.g. B. linear friction welding, can be attached to the hub / disc.

The gas turbine engines described and / or claimed here may or may not be provided with a VAN (Variable Area Nozzle). Such a nozzle with a variable cross-section can allow the exit cross-section of the bypass channel to be varied in use. The general principles of the present disclosure may apply to engines with or without a VAN.

The fan of a gas turbine described and / or claimed herein can have any desired number of fan blades, for example 16, 18, 20 or 22 fan blades.

As used herein, it may mean constant velocity conditions of an aircraft on which the gas turbine engine is mounted. Such constant speed conditions can conventionally be defined as the conditions during the middle part of the flight, for example the conditions to which the aircraft and / or the engine are exposed between (in terms of time and / or distance) the end of the climb and the start of the descent. will.

By way of example only, the forward speed under the constant speed condition may be at any point in the range Mach 0.7-0.9, e.g. 0.75-0.85, e.g. 0.76-0.84, e.g. 0.77-0 .83, for example 0.78 to 0.82, for example 0.79 to 0.81, for example in the order of Mach 0.8, in the order of Mach 0.85 or in the range from 0.8 to 0, 85 lie. Any speed within these ranges can be the constant travel condition. In some aircraft, the cruise control conditions may be outside of these ranges, for example below Mach 0.7 or above Mach 0.9.

By way of example only, the constant velocity conditions may mean standard atmospheric conditions at an altitude that is 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 (about 38,000 feet), for example in Range from 10,500 m to 11,500 m, for example in the range from 10,600 m to 11,400 m, for example in the range from 10,700 m (about 35,000 feet) to 11,300 m, for example in the range from 10,800 m to 11,200 m, for example in the range from 10,900 m to 11,100 m, for example in the order of 11,000 m, correspond. The constant velocity conditions can correspond to standard atmospheric conditions at any given altitude in these areas.

By way of example only, the constant speed conditions may correspond to: a forward Mach number of 0.8; a pressure of 23,000 Pa and a temperature of -55 degrees C. .

As they are used throughout here, “constant speed” or “constant speed conditions” can mean the aerodynamic design point. Such an aerodynamic design point (or ADP) may correspond to the conditions (including, for example, Mach number, environmental conditions, and thrust requirement) for which the blower is designed to operate. For example, the conditions under which the fan (or gas turbine engine) has the optimal efficiency according to the design, mean.

In use, a gas turbine engine described and / or claimed herein can be operated at the constant speed conditions defined elsewhere herein. Such constant speed conditions may be determined by the constant speed conditions (e.g., conditions during the middle part of flight) of an aircraft to which at least one (e.g. 2 or 4) gas turbine engine may be attached to provide thrust.

It will be understood by those skilled in the art that a feature or parameter described in relation to any of the above aspects can be applied to any other aspect, provided that they are not mutually exclusive. Furthermore, any feature or parameter described here can be applied to any aspect and / or combined with any other feature or parameter described here, insofar as they are compatible not mutually exclusive.

• 1 eine Seitenschnittansicht eines Gasturbinentriebwerks;
• 2 eine Seitenschnittgroßansicht eines stromaufwärtigen Abschnitts eines Gasturbinentriebwerks;
• 3 eine zum Teil weggeschnitte Ansicht eines Getriebes für ein Gasturbinentriebwerk;
• 4 ein Ausführungsbeispiel eines Planetengetriebes, das einen Planetenstift umfasst, der einen Hauptkörper, einen Lagerring und einen diese verbindenden, sich radial erstreckende Steg umfasst, wobei zwischen dem Hauptkörper und dem Lagerring zwei asymmetrisch ausgebildete Aussparungen ausgebildet sind;
• 5 eine vergrößerte Darstellung des Planetenstifts der 4;
• 6 eine erste Abwandlung des Planetenstifts der 4 und 5, wobei die beiden Aussparungen eine unterschiedliche radiale Höhe aufweisen;
• 7 eine zweite Abwandlung des Planetenstifts der 4 und 5, wobei die beiden Aussparungen eine unterschiedliche Geometrie aufweisen;
• 8 ein weiteres Ausführungsbeispiel eines Planetenstifts, der zur Verwendung in einem Planetengetriebe gemäß 4 geeignet ist, wobei der Planetenstift nur eine axiale Aussparung aufweist und sich der Steg an einem der axialen Ende des Planetenstifts erstreckt.

The invention is explained in more detail below with reference to the figures of the drawing on the basis of several exemplary embodiments. Show it:

• 1 a side sectional view of a gas turbine engine;
• 2 Fig. 3 is a side sectional close-up view of an upstream portion of a gas turbine engine;
• 3 a partially cut away view of a transmission for a gas turbine engine;
• 4th an embodiment of a planetary gear which comprises a planetary pin which comprises a main body, a bearing ring and a connecting, radially extending web, wherein two asymmetrically formed recesses are formed between the main body and the bearing ring;
• 5 an enlarged view of the planetary pin 4th ;
• 6th a first modification of the planetary pin 4th and 5 , wherein the two recesses have a different radial height;
• 7th a second modification of the planetary pin of the 4th and 5 , wherein the two recesses have a different geometry;
• 8th Another embodiment of a planetary pin, which is for use in a planetary gear according to 4th is suitable, wherein the planet pin has only one axial recess and the web extends at one of the axial ends of the planet pin.

1 represents a gas turbine engine 10 with a main axis of rotation 9 represent. The engine 10 includes an air inlet 12th and a thrust fan 23 , which creates two air flows: a core air flow A and a bypass air flow B. The gas turbine engine 10 includes a core 11 , which takes in the core air flow A. The engine core 11 includes, in axial flow order, a low pressure compressor 14th , a high pressure compressor 15th , an incinerator 16 , a high pressure turbine 17th , a low pressure turbine 19th and a core thrust nozzle 20th . An engine nacelle 21 surrounds the gas turbine engine 10 and defines a bypass channel 22nd and a bypass thrust nozzle 18th . The bypass air flow B flows through the bypass duct 22nd . The blower 23 is about a wave 26th and an epicycloidal gear 30th on the low pressure turbine 19th attached and is driven by this.

In use, the core air flow A is through the low pressure compressor 14th accelerated and compressed and in the high pressure compressor 15th where further compression takes place. The one from the high pressure compressor 15th compressed air is discharged into the incinerator 16 where it is mixed with fuel and the mixture is burned. The resulting hot products of combustion then propagate through the high pressure and low pressure turbines 17th , 19th and thereby drive them on before they are used to provide a certain thrust through the nozzle 20th be expelled. The high pressure turbine 17th drives the high pressure compressor 15th by means of a suitable connecting shaft 27 on. The blower 23 generally provides the majority of the thrust. The epicycloidal gear 30th is a reduction gear.

An exemplary arrangement for a geared blower gas turbine engine 10 is in 2 shown. The low pressure turbine 19th (please refer 1 ) drives the wave 26th at that with a sun gear 28 the epicycloidal gear assembly 30th is coupled. Several planet gears 32 by a planet carrier 34 are coupled to each other, are located by the sun gear 28 radially outside and mesh with it. The planet carrier 34 restricts the planet gears 32 on it, in sync with the sun gear 28 to orbit while allowing each planetary gear to move 32 can rotate around its own axis. The planet carrier 34 is about linkage 36 with the blower 23 coupled to that effect its rotation around the engine axis 9 to drive. An external gear or ring gear 38 that is about linkage 40 With a stationary support structure 24 is coupled, is located by the planet gears 32 radially outside and combs with it.

It should be noted that the terms “low-pressure turbine” and “low-pressure compressor” as used herein can be understood to mean the lowest pressure turbine stage and the lowest pressure compressor stage (i.e. not the fan 23 include) and / or the turbine and compressor stage through the connecting shaft 26th with the lowest speed in the engine (meaning that it is not the gearbox output shaft that controls the fan 23 drives, includes) are interconnected, mean. In some scriptures, the “low pressure turbine” and “low pressure compressor” referred to here may alternatively be known as the “medium pressure turbine” and “medium pressure compressor”. Using such alternative nomenclature, the fan 23 may be referred to as a first compression stage or the lowest pressure compression stage.

The epicycloidal gear 30th is in 3 shown in more detail as an example. The sun gear 28 who have favourited planet gears 32 and the ring gear 38 each include teeth around their periphery for meshing with the other gears. However, for the sake of clarity, only exemplary sections of the teeth are shown in FIG 3 shown. Although four planet gears 32 are shown, it is obvious to those skilled in the art that more or fewer planetary gears are within the scope of the claimed invention 32 can be provided. Practical applications of an epicycloidal gear 30th generally include at least three planetary gears 32 .

This in 2 and 3 epicycloidal gears shown by way of example 30th is a planetary gear in which the planet carrier 34 via linkage 36 is coupled to an output shaft, the ring gear 38 is fixed. However, any other suitable type of epicycloidal gear may be used 30th be used. As another example, the epicycloidal gear 30th be a star arrangement in which the planet carrier 34 fixed, allowing the internal gear (or external gear) to move 38 turns. With such an arrangement, the fan 23 from the ring gear 38 driven. As another alternative example, the transmission 30th be a differential gear that allows both the ring gear 38 as well as the planet carrier 34 rotate.

It goes without saying that the in 2 and 3 The arrangement shown is exemplary only and various alternatives are within the scope of the present disclosure. Any suitable arrangement for positioning the transmission can be used merely as an example 30th in the engine 10 and / or to connect the transmission 30th with the engine 10 be used. As another example, the connections (e.g. the linkages 36 , 40 in the example of 2 ) between the gearbox 30th and other parts of the engine 10 (such as the input shaft 26th , the output shaft and the established structure 24 ) have some degree of rigidity or flexibility. As a further example, any suitable arrangement of the bearings between rotating and stationary parts of the engine (e.g., between the input and output shafts of the gearbox and the fixed structures such as the gearbox housing) can be used and the disclosure is not to the exemplary arrangement of 2 limited. For example, it is readily apparent to a person skilled in the art that the arrangement of the output and support rods and bearing positions are different in the case of a star arrangement (described above) of the transmission 30th usually by those who exemplified in 2 would differ.

Accordingly, the present disclosure extends to a gas turbine engine having any arrangement of gear types (e.g., star or planetary), support structures, input and output shaft arrangements, and bearing positions.

Optionally, the transmission can drive secondary and / or alternative components (e.g. the medium-pressure compressor and / or a booster).

Other gas turbine engines to which the present disclosure may find application may have alternative configurations. For example, such engines can have an alternative number of compressors and / or turbines and / or an alternative number of connecting shafts. As another example, the 1 The gas turbine engine shown has a split flow nozzle 20th , 22nd on, which means that the flow through the bypass duct 22nd has its own nozzle, that of the engine core nozzle 20th is separate and radially outward therefrom. However, this is not limiting and any aspect of the present disclosure may also apply to engines in which the flow is through the bypass duct 22nd and the current through the core 11 mixed or combined in front of (or upstream) a single nozzle which may be referred to as a mixed flow nozzle. One or both nozzles (whether mixed or split flow) can have a fixed or variable range. For example, while the example described relates to a turbo fan engine, the disclosure may be applied to any type of gas turbine engine such as a gas turbine engine. B. with an open rotor (in which the fan stage is not surrounded by an engine nacelle) or a turboprop engine. In some arrangements, the gas turbine engine comprises 10 possibly no transmission 30th .

The geometry of the gas turbine engine 10 and components thereof is or are defined by a conventional axis system that has an axial direction (that of the axis of rotation 9 aligned), a radial direction (in the direction from bottom to top in 1 ) and a circumferential direction (perpendicular to the view in 1 ) includes. The axial, radial and circumferential directions are perpendicular to one another.

the 4th shows an embodiment of a planetary gear of a gas turbine engine 10 according to the 1 in a sectional view. It should be noted that the planetary gear described is only used as an example in a gas turbine engine. In principle, the planetary gear can be designed in any context in the manner described below.

The planetary gear 30th includes a sun gear 28 , which is driven by a drive shaft or sun shaft (not shown). The drive shaft is, for example, the shaft 26th the 1 and 2 or generally around a turbine shaft. The sun gear and the drive shaft 26th rotate around the axis of rotation 9 . The axis of rotation of the planetary gear 30th is identical to the axis of rotation 9 or machine axis of the gas turbine engine 10 .

The planetary gear 30th further comprises a plurality of planet gears 32 , of which in the sectional view of the 4th one is shown. The sun gear 28 drives the majority of the planetary gears 32 on, with a toothing of the sun gear 28 with a toothing of the planetary gear 32 is engaged.

The planet gear 32 rotates - driven by the sun gear 28 - around an axis of rotation 90 that are parallel to the axis of rotation 9 runs.

The outer surface of the planetary gear 32 forms a toothing that connects to the toothing of a ring gear 38 is engaged. The ring gear 38 is fixed, ie arranged in a non-rotating manner. The planet gears 32 rotate due to their coupling with the sun gear 28 and migrate along the circumference of the ring gear 38 . The rotation of the planet gears 32 along the circumference of the ring gear 38 and around the axis of rotation 90 is slower than the rotation of the drive shaft (see e.g. drive shaft 26th the 1 and 2 ), whereby a reduction is provided.

It should be noted, however, that the present invention is not limited to planetary gears with a stationary ring gear. It can also be implemented in planetary gears with a stationary planet carrier and rotating ring gear.

The planet gear 32 has a centered inner axial bore or opening adjacent to its inner lateral surface 320 on. In the opening 320 A planetary pin is inserted 6th who also has an axial bore itself 60 having, the planetary pin 6th and the planetary gear 32 a plain bearing on their facing surfaces 7th or form the plain bearing gap.

Alternatively it can be provided that the planetary pin 6th and the planetary gear 32 instead of a plain bearing, form a roller bearing. If the following description relates to a plain bearing, this is to be understood as an example. When the bearing is designed as a roller bearing, roller bodies are located between the planetary pin in a manner known per se 6th and the planetary gear 32 arranged. It can be provided that profiles for receiving the rolling elements are formed on the outside or running surface of the planetary pin.

Furthermore, it can alternatively be provided that the planetary pin 6th has no axial bore and is fully executed.

the 4th also shows a front support plate 81 and a rear support plate 82 , which form a planet carrier, compare 2 . The planet pin 6th has a hollow cylindrical main body 61 on that of the axial bore 60 has and at its axial ends with the front support plate 81 and with the rear support plate 82 is attached. To do this, both the front carrier plate 81 as well as the rear carrier plate 82 a mounting hole 810 , 820 on, in which the axial end regions 615 , 616 of the main body 61 are used in a known manner. It can be provided that the two fastening openings 810 , 820 have the same or a different diameter.

The front support plate 81 is connected, for example, to a torque carrier which is coupled to a fan shaft. The by the wandering of the planet gears 32 in the ring gear 38 triggered rotation of the carrier plate 81 around the axis of rotation 9 is transmitted to the fan wave.

The following description of the planetary pin 6th additionally refers to the 5 who have favourited the planet pin 6th the 4th shows in an enlarged view. The 5 (as well as the following 6th until 8th ) only the upper part of the Planet pin 6th the 4th . The planet pin 6th is each designed to be rotationally symmetrical.

The planet pin 6th faces one to the main body 61 radially spaced sliding bearing ring 62 on who the plain bearing 7th with the planet gear 32 forms. To connect the main body 61 with the plain bearing ring 62 is a radially extending web 63 intended. The main body 61 , the plain bearing ring 62 and the bridge 63 are one-piece components of the planetary pin 6th . Instead of a bridge 63 Several webs can also be provided, which are axially spaced from one another.

The hollow cylindrical main body 61 has an inner surface 610 on which the axial bore 60 limited. The main body 61 also has an outer surface 611 on which an axially front recess 41 and an axially rear recess 42 in the planet pen 6th limited radially inside. The axial end areas 615 , 616 of the main body 61 are in the axially front support plate 81 and the axially rear support plate 82 non-rotatably mounted.

The plain bearing ring 62 has an outer surface 620 on which the bearing surface of the planetary pin 6th forms that with the inner surface of the planetary gear 32 the warehouse 7th forms. The plain bearing ring 62 also forms an inner surface 621 who have favourited the cutouts 41 , 42 in the planet pen 6th limited radially outside. The recesses 41 , 42 each extend starting from the axially front end 601 and from the axially rearward end 602 of the planetary pin 6th between the main body 61 and the plain bearing ring 62 to the jetty 63 . The axial length L3 , L4 of the recesses 41 , 42 is determined by the axial distance between the respective end face 625 , 626 of the plain bearing ring 62 and the jetty 63 .

It is provided that the web 63 off-center and at the same time opposite the axial center M. of the planetary pin is arranged shifted axially backwards, so that the axially front recess 41 a greater axial length L3 possesses than the axially rear recess 42 which is the axial length L4 owns. As the axial center M. of the planetary pin 6th becomes the axial center of the plain bearing ring 62 considered as the length L1 of the plain bearing ring 32 along with the axial length L2 of the jetty 63 the axial length of the recesses 41 , 42 Are defined.

Alternatively it can be provided that the web 63 opposite the axial center M. of the planet pin is shifted axially forward.

The bridge 63 has two side walls 631 , 632 which are each concave and smooth, that is, without the formation of edges in the radially outer and radially inner delimitation of the respective recess 41 , 42 , ie in the inner surface 621 of the plain bearing ring 62 and the outer surface 611 of the main body.

The bridge 63 has an axial length L2 due to the axial distance between the side walls 631 , 632 is defined, where the axial length L2 in the radial center between the outer surface 611 of the main body 61 and the inner surface 621 of the plain bearing ring 62 is measured. The axial length L1 of the plain bearing ring 62 is equal to the sum of the lengths L2 , L3 and L4 .

It can be provided, for example, that the ratio of the axial length L1 of the plain bearing ring 62 to the axial length L2 of the jetty 63 lies in the range between 1.3 and 30, with the corner points belonging to the range.

Next point the recesses 41 , 42 a radial height C. on, which in the embodiment of 4th and 5 but not necessarily for both slots 41 , 42 is identical and constant in each case.

The main body has due to the areas 615 , 616 that are in the carrier plates 81 , 82 are attached one length L5 on that is greater than the length L1 of the plain bearing ring 62 .

In the embodiment of 4th and 5 are the recesses 41 , 42 in the planet pen 6th insofar asymmetrically based on the axial center M. of the planetary pin 6th formed as they have a different axial length L3 , L4 exhibit.

In the 6th until 8th are further examples of an asymmetrical arrangement of the recesses 41 , 42 in the planet pen 6th described. This is where the planetary pin 6th only described insofar as it is different from the embodiment of 4th and 5 is trained. Otherwise, refer to the description of the 4th and 5 referenced.

the 6th shows an embodiment in which the axially front recess 411 a smaller radial height C1 has than the axially rear recess 421 that is the radial height C2 has: C1 / C2 <1. To the different radial heights C1 , C2 to realize, has the plain bearing ring 62 in its axially anterior region 622 , of the axially anterior recess 411 limited radially on the outside, a greater radial thickness than in its axially rear region 623 showing the axially rear recess 421 limited radially outside. The different radial heights C1 , C2 of the recesses 411 , 421 also lead to the axially front side wall 631 of the jetty 63 has a greater curvature than the axially rear side wall 632 of the jetty 63 .

Alternatively, the ratios can be reversed, ie C2 / C1 <1.

In the embodiment of 6th is both over a different axial length and a different radial height of the recesses 411 , 421 an asymmetry of the recesses 411 , 421 in the planet pen 6th provided.

the 7th shows an embodiment in which the axially front recess 413 a radial height C. has, which is not constant, but with increasing distance from the axially front end 601 of the planetary pin 6th decreases so that the recess 413 towards the footbridge 63 rejuvenates. However, this is only to be understood as an example. In alternative configurations it can be provided that the radial height C. towards the jetty 63 increases or the recess 413 towards the jetty 63 widened. Furthermore, defined profiles of the radial height can also be used C. be realized, the radial height C. for example in a first axial section of the recess 61 increases and in an adjoining axial section of the recess 61 decreases or vice versa. More complicated curves of the radial height can also be used C. be implemented as a function of the axial position.

Alternatively, a radial height that changes as a function of the axial position can be used C. also in the axially rear recess 42 or in both recesses 413 , 42 be realized.

With the dependence of the radial height C. from the axial position goes hand in hand with that of the radial thickness of the main body 61 and / or the radial thickness of the bearing ring 62 also changes depending on the axial position.

The one in the 7th shown variation of the radial height C. the recess 413 represents an example of a different geometry of the two recesses, through which, in addition to the different axial length of the recesses 413 , 42 an asymmetry of the two recesses is defined. A different geometry is understood to mean, in particular, that the radially outer and / or the radially inner delimitation of the respective recess have a different axial profile in the sectional view.

In this case, in an alternative exemplary embodiment, an asymmetry can only be achieved through a different geometry of the recesses 413 , 42 be defined, with a central arrangement of the web 63 .

the 8th shows an embodiment in which the planetary pin 6th only one axial recess 41 having. The radially extending web is accordingly 63 at one of the axial ends of the planetary pin 6th arranged. In the initial example of the 8th is the jetty 63 at the axially rear end 602 of the planetary pin 6th educated. However, the relationships can also be reversed, for which case the web 63 at the axially front end 601 of the planetary pin 6th trained is.

The recess 41 has in the embodiment of 8th a constant radial height C. on. However, this is only to be understood as an example. Alternatively it can be provided that the radial height C. the recess 41 varies depending on the axial position, for example according to the recess 413 of the embodiment of 7th .

In general, the front and rear carrier plates 81 , 82 can be made of one piece, ie are firmly connected to each other. Such a configuration is also referred to as a one-piece planet carrier. In this case, one of the fastening openings must be at least as large as the outer diameter of the bearing ring. Alternatively, a multi-piece planet carrier can be provided. The aforementioned restriction does not apply to a multi-part planet carrier.

It should be understood that the invention is not limited to the embodiments described above and various modifications and improvements can be made without departing from the concepts described herein. For example, the web 63 have a different contour, for example side walls 631 , 632 have, which run in a straight line in the radial direction in the sectional view. Further design variants can provide that the recesses 41 , 42 or one of the recesses 41 , 42 do not extend over the full angular range of 360 ° in the circumferential direction.

It is pointed out that any of the features described can be used separately or in combination with any other features, provided that they are not mutually exclusive. The disclosure extends to and includes all combinations and subcombinations of one or more features described herein. If areas are defined, they include all values within these areas as well as all sub-areas that fall into one area.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102017127876 A1 [0002]
• US 2016/0201793 A1 [0005]

Claims (19)

Planetary gear, which has: - a sun gear (28) which rotates about an axis of rotation (9) of the planetary gear (30) and can be driven by a sun shaft, the axis of rotation (9) defining an axial direction of the planetary gear (30), - a A plurality of planet gears (32) which are driven by the sun gear (28), - a ring gear (38) with which the plurality of planet gears (32) meshes, - a plurality of planetary pins (6), one planetary pin in each case (6) is arranged in a planet gear (32) and the planet pin (6) and the planet gear (32) form a bearing (7), characterized in that the planet pin (6) has a main body (61) and a main body (61 ) forms a radially spaced bearing ring (62) which forms the bearing (7) with the planetary gear (32), wherein - the main body (61) and the bearing ring (62) are connected to one another via at least one radially extending web (63), - at least one recess (41, 42) is provided, which extends from the axially front end (601) or from the axially rear end (602) of the planetary pin (6) between the main body (61) and the bearing ring (62) to the at least one web (63), and - in the case of two recesses (41, 42) these are formed asymmetrically with respect to the axial center (M) of the planetary pin (6) in the planetary pin (6). Planetary gear according to Claim 1 , characterized in that the main body (61) is cylindrical. Planetary gear according to Claim 1 or 2 , characterized in that the main body (61) has an axial bore (60) through it. Planetary gear according to one of the preceding claims, characterized in that the at least one web (63) which connects the main body (61) and the bearing ring (62) is arranged eccentrically. Planetary gear according to one of the preceding claims, characterized in that the planetary pin (6) has two recesses (41, 42) which each extend from one of the ends (601, 602) of the planetary pin (6). Planetary gear according to Claim 5 , characterized in that the two recesses (41, 42) have different axial lengths (L3, L4). Planetary gear according to Claim 5 or 6th , characterized in that the two recesses (411, 421) have different radial heights (C1, C2). Planetary gear according to one of the Claims 5 until 7th , characterized in that the two recesses (413, 42) have a different geometry in longitudinal section. Planetary gear according to one of the Claims 5 until 8th , characterized in that the radial height (C) of at least one of the recesses (413) decreases with increasing distance from the corresponding end (601) of the planetary pin (6). Planetary gear according to one of the Claims 5 until 9 , characterized in that at least one of the recesses (41, 42) is essentially rectangular in longitudinal section. Planetary gear according to one of the Claims 1 until 4th , characterized in that the planet pin (6) has only one axial recess (41), the radially extending web (63) being arranged on one of the axial ends (602) of the planet pin (6). Planetary gear according to one of the preceding claims, characterized in that the bearing ring (62) has a smaller axial length (L1) than the main body (61). Planetary gear according to one of the preceding claims, characterized in that the planet pin (6) at its axially front end (601) on an axially front carrier plate (81) and at its axially rear end (602) on an axially rear carrier plate (82) of the Planetary gear (30) is attached. Planetary gear according to Claim 13 , characterized in that only the main body (61) is connected at its axial ends (615, 616) to the front and rear carrier plates (81, 82). Planetary gear according to Claim 14 , as far as referenced Claim 12 , characterized in that the bearing ring (62) is not connected to the front and rear carrier plates (81, 82) and has a smaller axial length (L1) than the main body (61). Planetary gear according to one of the preceding claims, characterized in that the web (3) has concave side walls (631, 632) which smoothly, without the formation of edges, into a radially outer boundary (621) and into a radially inner boundary ( 611) of the respective recess (41, 42). Planetary gear according to one of the preceding claims, characterized in that the at least one recess (41, 42) extends over 360 ° in the circumferential direction of the planetary pin. Planetary gear according to one of the preceding claims, characterized in that the main body (61), the at least one web (63) and the bearing ring (62) are formed in one piece. Gas turbine engine (10) for an aircraft, comprising: - an engine core (11) which comprises a turbine (19), a compressor (14) and a turbine shaft (26) which connects the turbine to the compressor and is designed as a hollow shaft; - A fan (23) positioned upstream of the engine core (11), the fan (23) comprising a plurality of fan blades and being driven by a fan shaft; and - a planetary gear (30) according to Claim 1 , whose input is connected to the turbine shaft (26) and whose output is connected to the fan shaft.

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