GEARBOX AND GAS TURBINE PROPULSION UNIT

Abstract

The invention describes a transmission (30) having a rotatably mounted component (34) that is designed with at least two approximately rotationally symmetrical channels (41, 141) into which oil from a respective oil supply (44, 144) fixed to the housing can be introduced proceeding from the respective radially inner region (42, 142) of said channels. In at least one radially outer region (45, 145), the channels (41, 141) each have at least one outlet opening (46, 146) for the oil. Furthermore, the oil can be conveyed from the outlet openings (46, 146) to at least one hydraulic consumer via at least one line region (47, 147) in each case. A gas turbine engine having the transmission (30) is also proposed.

Claims

1. A transmission (30) with a rotatably mounted component (34), which is designed with at least two approximately rotationally symmetrical channels (41, 141), into each of which oil from a respective oil supply (44, 144) fixed to the housing can be introduced, starting from the radially inner region (42, 142) of said channels, wherein in at least one radially outer region (45, 145), the channels (41, 141) each have at least one outlet opening (46, 146) for the oil, and wherein the oil can be conveyed from the outlet openings (46, 146) to at least one hydraulic consumer via at least one respective line region (47, 147).

2. The transmission as claimed in claim 1, characterized in that supply line cross-sections of the oil supplies (44, 144) correspond to one another.

3. The transmission as claimed in claim 1, characterized in that supply line cross-sections of the oil supplies (44, 144) differ from one another.

4. The transmission as claimed in any of claims 1 to 3, characterized in that radial depths (T41, T141) of the channels (41, 141) differ from one another.

5. The transmission as claimed in any of claims 1 to 3, characterized in that radial depths (T41, T141) of the channels (41, 141) correspond to one another.

6. The transmission as claimed in any of claims 1 to 5, characterized in that cross-sections of the line regions (47, 147) correspond to one another.

7. The transmission as claimed in any of claims 1 to 5, characterized in that cross-sections of the line regions (47, 147) differ from one another.

8. The transmission as claimed in any of claims 1 to 7, characterized in that the line regions (47, 147) comprise opening regions (49, 149) which are each arranged in the region of hydraulic consumers in the planetary gear mechanism, and via which the hydraulic consumers can be loaded with oil.

9. The transmission as claimed in claim 8, characterized in that radial distances (R49, R149) between the opening regions (49, 149) and a rotational axis (70) of the component (34) are each larger and/or smaller than radial distances between the outlet openings (46, 146) of the channels (41, 141) and the rotational axis (70), or the radial distances (R49, 149) between the opening regions (49, 149) and the rotational axis (70) of the component (34) are the same as the radial distances between the outlet openings (46, 146) of the channels (41, 141) and the rotational axis (70).

10. The transmission as claimed in any of claims 1 to 9, characterized in that the channels (41, 141) are arranged on the same side of the component (34).

11. The transmission as claimed in any of claims 1 to 9, characterized in that at least one of the channels (41) is arranged on one side of the component (34), and at least a further one of the channels (141) is arranged on the side opposite thereto in the axial extent of the component (34).

12. The transmission as claimed in any of claims 1 to 11, characterized in that infeed directions (E, E100; E′, E100′) of the oil into the channels (41, 141), starting from the oil supplies (44, 144; 44′, 144′), each enclose an angle (α′) between 45° and 135° with the axial extent direction (z) of the channels (41, 141), while the infeed directions (E, E100; E′, E100′) of the oil in the circumferential direction of the channels (41, 141) each enclose an angle (β) with the radial extent direction (y) which is greater than or equal to 0° and less than 90°.

13. The transmission as claimed in any of claims 1 to 11, characterized in that the infeed directions (E′, E100′) of the oil into the channels (41, 141), starting from the oil supplies (44′, 144′), each enclose an angle (α′) between 75° and 90°, preferably between 80° and 90°, with the axial extent direction (z) of the channels (41, 141).

14. The transmission as claimed in any of claims 1 to 13, characterized in that oil can be conducted out of the channels (41, 141) via the outlet openings (46, 146) in the direction of the bearing and/or a toothing.

15. The transmission as claimed in any of claims 1 to 14, characterized in that the component (34) is a rotating shaft, preferably a sun gear (28), a planet carrier, a planet gear (32) and/or a ring gear (38).

16. A gas turbine engine (10) for an aircraft, comprising the following: an engine core (11) which comprises a turbine (19), a compressor (14), and a core shaft (26) that connects the turbine (19) to the compressor (14); a fan (23) which is positioned upstream of the engine core (11), wherein the fan (23) comprises multiple fan blades; and a transmission (30), which receives an input from the core shaft (26) and outputs drive for the fan (23) in order to drive the fan (23) at a lower speed than the core shaft (26), wherein the transmission (30) is configured as a planetary gear mechanism as claimed in any of claims 1 to 15.

17. The gas turbine engine as claimed in claim 16, characterized in that the turbine is a first turbine (19), the compressor is a first compressor (14), and the core shaft is a first core shaft (26); the engine core (11) furthermore comprises a second turbine (17), a second compressor (15) and a second core shaft (27) which connects the second turbine (17) to the second compressor (15); and the second turbine (17), the second compressor (15) and the second core shaft (27) are arranged so as to rotate at a higher rotational speed than the first core shaft (26).

Description

[0058] Embodiments will now be described, by way of example, with reference to the figures.

[0059] in which:

[0060] FIG. 1 shows a longitudinal sectional view of a gas turbine engine;

[0061] FIG. 2 shows an enlarged partial longitudinal sectional view of an upstream portion of a gas turbine engine;

[0062] FIG. 3 shows an isolated illustration of a transmission for a gas turbine engine;

[0063] FIG. 4 shows a sectional view of an embodiment of the transmission along a section line IV-IV denoted more specifically in FIG. 3;

[0064] FIG. 5 shows an illustration corresponding to FIG. 4 of a further embodiment of the transmission;

[0065] FIG. 6 shows an illustration corresponding to FIG. 4 of a further embodiment of the transmission;

[0066] FIG. 7 shows a first embodiment of an oil circuit of the gas turbine engine from FIG. 1; and

[0067] FIG. 8 shows an illustration corresponding to FIG. 7 of a second embodiment of the oil circuit.

[0068] FIG. 1 illustrates a gas turbine engine 10 with a main axis of rotation 9. The engine 10 comprises an air intake 12 and a thrust fan 23 that generates two airflows: a core airflow A and a bypass airflow B. The gas turbine engine 10 comprises a core 11 that receives the core airflow A. In the sequence of axial flow, the engine core 11 comprises 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 thrust nozzle 20. An engine nacelle 21 surrounds the gas turbine engine 10 and defines a bypass duct 22 and a bypass thrust nozzle 18. The bypass air flow B flows through the bypass duct 22. The fan 23 is attached to and driven by the low-pressure turbine 19 by way of a shaft 26 and an epicyclic transmission 30. The shaft 26 herein is also referred to as the core shaft.

[0069] During use, the core air flow A is accelerated and compressed by the low-pressure compressor 14 and directed into the high-pressure compressor 15, where further compression takes place. The compressed air expelled from the high-pressure compressor 15 is directed into the combustion device 16, where it is mixed with fuel and the mixture is combusted. The resulting hot combustion products then propagate through the high-pressure and the low-pressure turbines 17, 19 and thereby drive said turbines, before being expelled through the nozzle 20 to provide a certain propulsive thrust. The high-pressure turbine 17 drives the high-pressure compressor 15 by way of a suitable connecting shaft 27, which is also referred to as the core shaft. The fan 23 generally provides the majority of the propulsion force. The epicyclic transmission 30 is a reduction transmission.

[0070] An exemplary arrangement for a geared fan gas turbine engine 10 is shown in FIG. 2. The low-pressure turbine 19 (see FIG. 1) drives the shaft 26, which is coupled to a sun gear 28 of the epicyclic transmission arrangement 30. Multiple planet gears 32, which are coupled to one another by means of a planet carrier 34, are situated radially outside the sun gear 28 and mesh with the latter, and are in each case arranged so as to be rotatable on carrier elements 29 which are connected in a rotationally fixed manner to the planet carrier 34. The planet carrier 34 limits the planet gears 32 to orbiting around the sun gear 28 in a synchronous manner while enabling each planet gear 32 to rotate about its own axis on the carrier elements 29. The planet carrier 34 is coupled by way of linkages 36 to the fan 23 so as to drive the rotation of the latter about the engine axis 9. Radially to the outside of the planet gears 32 and meshing therewith is an annulus or ring gear 38 that is coupled, via linkages 40, to a stationary support structure 24.

[0071] It is noted that the terms “low-pressure turbine” and “low-pressure compressor” as used herein can be taken to mean the lowest pressure turbine stage and the lowest pressure compressor stage (that is to say not including the fan 23) respectively and/or the turbine and compressor stages that are connected to one another by the connecting shaft 26 with the lowest rotational speed in the engine (that is to say not including the transmission output shaft that drives the fan 23). In some documents, the “low-pressure turbine” and the “low-pressure compressor” referred to herein may alternatively be known as the “intermediate-pressure turbine” and “intermediate-pressure compressor”. Where such alternative nomenclature is used, the fan 23 can be referred to as a first compression stage or lowest-pressure compression stage.

[0072] The epicyclic transmission 30 is shown in greater detail by way of example in FIG. 3. Each of the sun gear 28, the planet gears 32 and the ring gear 38 comprise teeth about their periphery to mesh with the other gears. However, for clarity, only exemplary portions of the teeth are illustrated in FIG. 3. Although four planet gears 32 are illustrated, it will be apparent to the person skilled in the art that more or fewer planet gears 32 may be provided within the scope of protection of the claimed invention. Practical applications of an epicyclic transmission 30 generally comprise at least three planet gears 32.

[0073] The epicyclic transmission 30 illustrated by way of example in FIGS. 2 and 3 is of the planetary type, in which the planet carrier 34 is coupled to an output shaft via linkages 36, wherein the ring gear 38 is fixed. However, any other suitable type of epicyclic transmission 30 can be used. By way of further example, the epicyclic transmission 30 can be a star arrangement, in which the planet carrier 34 is held so as to be fixed, wherein the ring gear (or annulus) 38 is allowed to rotate. In the case of such an arrangement, the fan 23 is driven by the ring gear 38. As a further alternative example, the transmission 30 can be a differential transmission in which both the ring gear 38 and the planet carrier 34 are allowed to rotate.

[0074] It will be appreciated that the arrangement shown in FIGS. 2 and 3 is merely exemplary, and various alternatives fall within the scope of protection of the present disclosure. Purely by way of example, any suitable arrangement can be used for positioning the transmission 30 in the engine 10 and/or for connecting the transmission 30 to the engine 10. By way of a further example, the connections (such as the linkages 36, 40 in the example of FIG. 2) between the transmission 30 and other parts of the engine 10 (such as the input shaft 26, the output shaft and the fixed structure 24) may have a certain degree of stiffness or flexibility. By way of a further example, any suitable arrangement of the bearings between rotating and stationary parts of the engine (for example between the input and output shafts of the transmission and the fixed structures, such as the transmission casing) may be used, and the disclosure is not limited to the exemplary arrangement of FIG. 2. For example, where the transmission 30 has a star arrangement (described above), a person skilled in the art will readily understand that the arrangement of output and support linkages and bearing positions would usually be different than that shown by way of example in FIG. 2.

[0075] Accordingly, the present disclosure extends to a gas turbine engine having an arbitrary arrangement of transmission types (for example star-shaped or planetary), support structures, input and output shaft arrangement, and bearing positions.

[0076] Optionally, the transmission may drive additional and/or alternative components (e.g. the intermediate-pressure compressor and/or a booster compressor).

[0077] Other gas turbine engines in which the present disclosure can be used may have alternative configurations. For example, such engines may have an alternative number of compressors and/or turbines and/or an alternative number of connecting shafts. By way of further example, the gas turbine engine shown in FIG. 1 has a split flow nozzle 20, 22, meaning that the flow through the bypass duct 22 has a dedicated nozzle that is separate from and radially outside the engine core nozzle 20. However, this is not restrictive, and any aspect of the present disclosure can also apply to engines in which the flow through the bypass duct 22 and the flow through the core 11 are mixed or combined before (or upstream of) 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 region. Although the example described relates to a turbofan engine, the disclosure can be applied, for example, to any type of gas turbine engine, such as, for example, an open rotor engine (in which the fan stage is not surrounded by an engine nacelle) or a turboprop engine.

[0078] The geometry of the gas turbine engine 10, and components thereof, is or are defined using a conventional axis system which comprises an axial direction (which is aligned with the axis of rotation 9), a radial direction (in the direction from bottom to top in FIG. 1), and a circumferential direction (perpendicular to the view in FIG. 1). The axial, radial and circumferential directions run so as to be mutually perpendicular.

[0079] FIG. 3 and FIG. 4 show an orientation of the transmission 30 in its installation position in the gas turbine engine 10 during a horizontal flight of an aircraft equipped with a gas turbine engine 10. The rotatable planet carrier 34 of the transmission 30 is formed with a rotationally symmetrical channel 41, 141 on both its side facing the shaft 26 and on its side facing away from the shaft 26, in the manner shown in more detail in FIG. 3 and FIG. 4. The channels 41, 141 are arranged coaxially to the rotational axis of the planet carrier 34 and sun gear 28, and in radially inner regions 42, 142 are each configured with an opening extending in the circumferential direction of the channel 41, 141. Starting from mutually corresponding radial inner diameters Di41, Di141 of the channels 41, 141, oil can be conducted out of oil supplies 44, 144 fixed to the housing, through the openings 43, 143, into the channels 41, 141 which have approximately the same channel width.

[0080] Infeed directions E, E100 of the oil into the channels 41, 141, starting from the oil supplies 44, 144, each run parallel to an xy plane and thus enclose an angle α equal to 90° with the axial extent direction z of the channels 41, 141. With an angle α of 90°, oil is introduced into the channels 41, 141 in the y direction, i.e. radially outward. Furthermore, the infeed directions E, E100 of the oil into the channels 41, 141 intersect a yz plane and, depending on the respective application, enclose an angle β with the radial extent direction y which is greater than or equal to 0° and less than 90°. Here, with an angular value of the angle β which is equal to 90°, the oil is introduced tangentially into the channels 41, 141 and in the rotational direction of the channels 41, 141. In contrast, the infeed directions E, E100 are the same as the y direction when the angle β is equal to 0°.

[0081] Alternatively, it is also possible that, as shown in more detail in FIG. 4, the infeed directions E′, E100′ of the oil into the channels 41, 141, starting from the oil supplies 44′, 144′, each enclose an angle α′ between 45° and 135°, preferably between 75° and 90° or between 80° and 90°, with the axial extent direction z of the channels 41, 141.

[0082] In order to be able to guide the oil introduced into the channels 41, 141, out of the channels 41, 141, for example in the region of the bearing of the planet gears 32, the channels 41, 141 each have a plurality of outlet openings 46, 146 for the oil arranged in a radially outer region 45, 145 and distributed over the periphery of the channels 41, 141. The oil, which is conducted into the channels 41, 141 via the oil supplies 44, 144 with a desired impulse and then, in addition to the applied impulse, is accelerated outwards in the radial direction y by the centrifugal force acting on the oil in the channels 41, 141 as the planet carrier 34 rotates, can initially be conducted out of the channels 41, 141 via the outlet openings 46, 146. From there, the oil is transferred in the axial direction z of the transmission 30 via line regions 47, 147 of the planet carrier 34. The line regions 47, 147 have stub lines 48, 148 running radially to the outside in the y direction, the opening regions 49, 149 of which each lie in the region of hydraulic consumers in the planetary gear mechanism, such as bearings of the planet gears 32.

[0083] It is possible here that the radial distances R49, R149 between the opening regions 49, 149 and a rotational axis 70 of the planet carrier 34 are each larger than radial distances between the outlet openings 46, 146 of the channels 41, 141 and the rotational axis 70. Then oil introduced into the respective channels 41, 141 is also accelerated downstream of the outlet openings 46, 146 up to the opening regions 49, 149 by the centrifugal force acting during operation, or is conveyed through the channels 41, 141, the line regions 47, 147 and the stub lines 48, 148 to the respective hydraulic consumers to be supplied.

[0084] The radial distance between the outlet openings 46, 146 of the channels 41, 141 and the rotational axis 70 in the present exemplary embodiments amounts to half an outer diameter Da41, Da141 of the channels 41, 141 in each case.

[0085] Furthermore, it may also be provided that the radial distances R49, R149 between the opening regions 49, 149 and the rotational axis 70 of the planet carrier 34 each correspond to or are smaller than the radial distances between the outlet openings 46, 146 of the channels 41, 141 and the rotational axis 70.

[0086] The oil supplies 44, 144 each comprise an oil nozzle 50, 150. Outlet openings 51, 151 of the oil nozzles 50, 150 are arranged spaced apart from the openings 43, 143 of the channels 41, 141 in the y direction or radial direction. The oil is expelled from the oil nozzles 50, 150 with defined supply pressure, and depending on the design of the outlet openings 51, 151 of the oil nozzles 50, 150, is injected or sprayed into the channels 41, 141 with such an impulse that the oil in the channels 41, 141 flows, starting from the openings 43, 143 of the channels 41, 141, substantially in the y direction or substantially radially outward to the outlet openings 46, 146 of the channels 41, 141. The aim is that oil is conducted via the outlet openings 46, 146 of the channels 41, 141 into the line regions 47, 147 with a flow speed which guarantees a desired oil supply to the bearings of the planet gears 32.

[0087] In the exemplary embodiment of the transmission 30 shown in FIG. 3 and FIG. 4, and oil nozzle 50, 150 is assigned to each channel 41, 141. Furthermore, the oil supplies 44, 144 may each comprise several oil nozzles 50, 150.

[0088] The oil nozzles arranged radially inside the channels 41, 141 may be positioned centrally, in the axial extent direction of the channels 41, 141, between the regions delimiting the channels 41, 141 in the axial direction. Then the introduced oil is conducted as evenly as possible over the axial width of the channels 41, 141.

[0089] Alternatively or additionally, the sun gear, planet gears and/or ring gear may be equipped with a channel in the fashion described above, into which oil can be conducted via a corresponding oil supply, in order to supply oil to hydraulic consumers in the transmission 30.

[0090] FIG. 5 shows an illustration corresponding to FIG. 4 of a further embodiment of the transmission 30, which corresponds substantially to the embodiment described in FIG. 4. For this reason, only the differences between the two embodiments are described in detail below. With respect to the fundamental function of the embodiment of the transmission 30 shown in FIG. 5, reference is made to the description relating to FIG. 4.

[0091] In the embodiment of the transmission 30 according to FIG. 5, the outer diameters Da41 and Da141 of the channels 41, 141 are equal. Furthermore, the inner diameter Di41 of the channel 41 is greater than the inner diameter Di141 of the channel 141, whereby a channel depth T141 of the channel 141 is greater than a channel depth T41 of the channel 41. Furthermore, the radial distances R49, R149 of the opening regions 49, 149 from the rotational axis 70 are the same. This gives the possibility that in operation of the transmission 30, if for example the same oil volume flow is introduced into the channels 41 and 141 from the oil supplies 44 and 144, a greater oil column will be set in the channel 141 and the respective hydraulic consumer will be loaded with a greater oil volume flow from the channel 141 than from the channel 41. This is the case for example if the oil volume flow supplied to the channels 41 and 141 is so large that the channel 41 overflows. Then only part of the oil volume flow supplied to the channel 41 is conducted in the direction of the opening regions 49, while the further part of the supplied oil volume flow flows out of the channel 41 over the inner edge of the channel 41 which is completely filled with oil, and is flung radially outward outside of the channel 41.

[0092] In an illustration corresponding to FIG. 4, FIG. 6 shows a further exemplary embodiment of the transmission 30, the function of which again corresponds substantially to the function of the transmission 30 from FIG. 4. The transmission 30 in FIG. 6 differs from the transmission 30 in FIG. 4 substantially only in that the two channels 41, 141 are arranged on the side of the planet carrier 34 facing the shaft 26, and the channel depth T141 of the channel 141 is smaller than the channel depth T41 of the channel 41. This is the case because the inner diameter Di141 of the channel 141 is greater than the inner diameter Di41 of the channel 41. In addition, the channel depths T141 and T41 differ from one another also because an outer diameter Da141 of the channel 141 is smaller than an outer diameter Da41 of the channel 41. The radial distances R49, R149 of the opening regions 49, 149 from the rotational axis 70 again correspond to one another.

[0093] FIG. 7 shows a first embodiment of an oil system 55 of the gas turbine engine 10. The oil system 55 comprises a first oil circuit 56 and a second oil circuit 57. The first oil circuit 56 and the second oil circuit 57 are fluidically coupled to a common output 59 of the transmission 30. Furthermore, the first oil circuit 56 and the second oil circuit 45 are each fluidically coupled to a separate inlet 61 and 62 of the transmission 30. The first oil circuit 56 and the second oil circuit 57 are each formed with a pump 62, 63 which is driven by the core shaft 26 or core shaft 27 respectively.

[0094] The outlet 59 of the transmission 30 comprises a device 64 which is designed to conduct oil from the transmission 30 into the first circuit 56 and the second oil circuit 57.

[0095] FIG. 8 shows a second embodiment of the oil system 55 of the gas turbine engine 10. The oil system 55 comprises the first oil circuit 56, the second oil circuit 57 and a third oil circuit 65. The first oil circuit 56, the second oil circuit 57 and the third oil circuit 65 are all fluidically actively connected to the output 59 of the transmission 30. Furthermore, the first oil circuit 56, the second oil circuit 57 and the third oil circuit 65 are each fluidically coupled to a separate inlet 60, 61, 66 of the transmission 30.

[0096] The first oil circuit 56 and the second oil circuit 57 each comprise a respective pump 62 and 63. In addition, the third oil circuit 65 is equipped with a pump 67 which is driven by the fan 23 or the core shaft 27, or by another suitable drive unit, e.g. an electric drive unit or similar. Oil is conducted from the outlet 59 of the transmission 30, again via the device 64, into the first oil circuit 56, the second oil circuit 57 and also the third oil circuit 65.

[0097] It will 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. Any of the features may be used separately or in combination with any other features, unless they are mutually exclusive, and the disclosure extends to and includes all combinations and subcombinations of one or more features which are described here.

LIST OF REFERENCE SIGNS

[0098] 9 Main axis of rotation [0099] 10 Gas turbine engine [0100] 11 Core [0101] 12 Air inlet [0102] 14 Low-pressure compressor [0103] 15 High-pressure compressor [0104] 16 Combustion device [0105] 17 High-pressure turbine [0106] 18 Bypass thrust nozzle [0107] 19 Low-pressure turbine [0108] 20 Core thrust nozzle [0109] 21 Engine nacelle [0110] 22 Bypass duct [0111] 23 Thrust fan [0112] 24 Support structure [0113] 26 Shaft, connecting shaft [0114] 27 Connecting shaft [0115] 28 Sun gear [0116] 30 Transmission, planetary gear mechanism [0117] 32 Planet gear [0118] 34 Planet carrier [0119] 36 Linkage [0120] 38 Ring gear [0121] 40 Linkage [0122] 41, 141 Channel [0123] 42, 142 Radially inner region of channel [0124] 43, 143 Opening [0125] 44, 144 Oil supply [0126] 45, 145 Radially outer region of channel [0127] 46, 146 Outlet opening [0128] 47, 147 Line region [0129] 48, 148 Stub line [0130] 49, 149 Opening region [0131] 50, 150 Oil nozzle [0132] 51, 151 Outlet opening [0133] 55 Oil system [0134] 56 First oil circuit [0135] 57 Second oil circuit [0136] 59 Outlet [0137] 60, 61 Inlet [0138] 62, 63 Pump [0139] 64 Device [0140] 65 Third oil circuit [0141] 66 Inlet [0142] 67 Pump [0143] 68 Valve unit [0144] 69 Duct [0145] 70 Rotational axis [0146] A Core air flow [0147] B Bypass air flow [0148] Di Inner diameter of channels [0149] Da Outer diameter of channels [0150] E Infeed direction [0151] R49, R149 Radial distance [0152] T41, T141 Channel depth [0153] α, α′ Angle [0154] β, β′ Angle