GAS TURBINE ENGINE OF AN AIRCRAFT COMPRISING A TRANSMISSION

Abstract

A gas turbine engine includes with a gear box is arranged radially in an interior space which is delimited by a support structure fixed with respect to a casing and which is provided radially within a core air flow. Shafts of the gear box are rotatably mounted in the support structure. The interior space is configured to be oil-tight in relation to the surroundings of the support structure, at least in a radially outer region. A pump unit is provided, by which oil is applied to the gear box and which is connected in terms of drive to the gear box. The support structure includes a receiving region for the pump unit. The pump unit can be introduced into the receiving region from a region outside the interior space via an opening of the support structure and can be removed from the receiving region via the opening.

Claims

1. A gas turbine engine of an aircraft with a gear box, which gear box is arranged at least partially radially in an interior space, which is delimited by a support structure fixed with respect to a casing and which is provided radially within a core air flow, of the support structure, wherein at least shafts of the gear box are rotatably mounted in the support structure wherein the interior space is configured to be oil-tight in relation to the surroundings of the support structure, at least in a radially outer region, wherein a pump unit is provided, by means of which oil can be applied to the gear box and which is connected in terms of drive to the gear box, and wherein the support structure is configured with a receiving region for the pump unit, into which receiving region the pump unit can be introduced from a region outside the interior space via an opening of the support structure and from which receiving region the pump unit can be removed via the opening.

2. The gas turbine engine as claimed in claim 1, wherein the pump unit projects into the interior space from the region outside the interior space through the opening of the support structure.

3. The gas turbine engine as claimed in claim 1, wherein a sealing unit is provided between a casing of the pump unit and the support structure in the region of the opening.

4. The gas turbine engine as claimed in claim 1, wherein a fan and a compressor are provided, between which the gear box is arranged in an axial direction and which are connected to one another via the gear box.

5. The gas turbine engine as claimed in claim 1, wherein, proceeding from a region facing toward the fan in the direction of a region facing toward the compressor, a radial spacing between a wall region of the support structure and an axis of rotation of the gas turbine engine initially increases to a maximum and then decreases again, wherein the maximum is provided at least approximately above that region between the fan and the compressor in which the gear box is arranged.

6. The gas turbine engine as claimed in claim 4, wherein the receiving region and the opening of the support structure are provided in that region of the support structure which faces toward the fan or in that region of the support structure which faces toward the compressor.

7. The gas turbine engine as claimed in claim 1, wherein the receiving region is provided entirely outside the interior space, outside and within the interior space, or entirely within the interior space.

8. The gas turbine engine as claimed in claim 1, wherein a drive shaft of the pump unit is operatively connected to a shaft of the gear box.

9. The gas turbine engine as claimed in claim 8, wherein a gear box unit is provided between the drive shaft of the pump unit and the shaft of the gear box.

10. The gas turbine engine as claimed in claim 4, wherein a first shaft of the gear box is connected to the fan via a fan shaft, and a second shaft of the gear box is operatively connected to the compressor via a compressor shaft.

11. The gas turbine engine as claimed in claim 10, wherein at least the first shaft of the gear box is rotatably mounted in that region of the support structure which faces toward the fan.

12. The gas turbine engine as claimed in claim 10, wherein at least the second shaft of the gear box is rotatably mounted in that region of the support structure which faces toward the compressor.

13. The gas turbine engine as claimed in claim 10, wherein the fan shaft and/or the compressor shaft are/is rotatably mounted in the support structure.

14. The gas turbine engine as claimed in claim 1, wherein a suction side of the pump unit is connected, preferably via an oil line which runs at least partially in the interior space of the support structure, to an oil reservoir.

15. The gas turbine engine as claimed in claim 1, wherein the pump unit comprises at least two pumps.

Description

[0060] Embodiments will now be described, by way of example, with reference to the figures.

[0061] in which:

[0062] FIG. 1 shows a longitudinal sectional view of a gas turbine engine;

[0063] FIG. 2 shows an enlarged partial longitudinal sectional view of an upstream portion of a gas turbine engine;

[0064] FIG. 3 shows an isolated illustration of a gear box for a gas turbine engine;

[0065] FIG. 4 shows a highly schematic illustration of the region shown in FIG. 2 of a further exemplary embodiment of the gas turbine engine, in which a pump is integrated in that region of the support structure which faces toward the fan;

[0066] FIG. 5 shows an illustration corresponding to FIG. 4 of a further exemplary embodiment of the gas turbine engine, in which the pump is integrated in a region of the support structure facing toward the compressor and is connected in terms of drive to a planet carrier of the gear box;

[0067] FIG. 6 shows an illustration corresponding to FIG. 5 of a further embodiment of gas turbine engine, in which the pump is connected in terms of drive to a compressor shaft;

[0068] FIG. 7 shows a schematic three-dimensional partial view of the support structure and of the pump unit in the uninstalled state of the pump unit;

[0069] FIG. 8 shows an illustration of the support structure and of the pump unit corresponding to FIG. 7 in the installed state of the pump unit; and

[0070] FIG. 9 shows a first embodiment of an oil circuit of the gas turbine engine according to FIG. 1.

[0071] 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 fan or a thrust fan 23 that generates two air flows: a core air flow A and a bypass air flow B. The gas turbine engine 10 comprises a core 11 which receives the core air flow A. In the sequence of axial flow, the engine core 11 comprises a compressor or 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 compressor shaft or a shaft 26 and a gear box or epicyclic gear box 30. The shaft 26 herein is also referred to as the core shaft.

[0072] 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 gear box 30 is a reduction gear box.

[0073] 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 gear box 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 and which are shown in more detail in FIG. 3. 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.

[0074] 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 gear box output shaft that drives the fan 23). In some documents, the “low-pressure tur- bine” 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.

[0075] The epicyclic gear box 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 gear box 30 generally comprise at least three planet gears 32.

[0076] The epicyclic gear box 30 illustrated by way of example in FIGS. 2 and 3 is a planetary gear box, in which the planet carrier 34 is coupled to a linkage 36 or to a fan shaft, wherein the ring gear 38 is fixed. However, any other suitable type of epicyclic gear box 30 may be used. As a further example, the epicyclic gear box 30 may be a star arrangement, in which the planet carrier 34 is held fixed, with the ring gear (or annulus) 38 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 gear box 30 can be a differential gear box in which both the ring gear 38 and the planet carrier 34 are allowed to rotate.

[0077] 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 gear box 30 in the engine 10 and/or for connecting the gear box 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 gear box 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 gear box and the fixed structures, such as the gear box casing) may be used, and the disclosure is not limited to the exemplary arrangement of FIG. 2. For example, where the gear box 30 has a star arrangement (described above), the person skilled in the art would readily understand that the arrangement of output and support linkages and bearing positions would usually be different from those shown by way of example in FIG. 2.

[0078] Accordingly, the present disclosure extends to a gas turbine engine having an arbitrary arrangement of gear box types (for example star-shaped or planetary), support structures, input and output shaft arrangement, and bearing positions.

[0079] Optionally, the gear box may drive additional and/or alternative components (for example the intermediate-pressure compressor and/or a booster compressor).

[0080] 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.

[0081] 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 X (which is aligned with the axis of rotation 9), a radial direction Y (in the direction from bottom to top in FIG. 1), and a circumferential direction U (perpendicular to the view in FIG. 1). The axial, radial and circumferential directions X, Y and U are mutually perpendicular.

[0082] The gear box 30 is, in the manner shown in more detail in each of FIGS. 4 to 6, arranged radially in an interior space 40 which is delimited by the support structure 24 fixed with respect to a casing and which is provided radially within the core air flow A. Furthermore, the planet carrier 34 and the sun gear 28, which is connected rotationally conjointly to the compressor shaft 26, are mounted rotatably in the support structure 24 by means of bearings 41 to 44. The fan shaft 36 is also mounted rotatably in the support structure 24 by means of the bearing 41. In addition, the compressor shaft 26 is supported on the support structure 24 via the bearing 44.

[0083] The interior space 40 is configured to be oil-tight in relation to the surroundings of the support structure 24, and in relation to the core air flow A, in a radially outer region 45. Oil that is sprayed from the gear box 30 during operation is captured and collected in the radially outer region 45. This avoids uncontrolled distribution of the oil in the gas turbine engine 10. The oil volume collected in the radially outer region is illustrated in more detail in the drawing at reference designation 13.

[0084] Furthermore, a pump unit 46 is provided, by means of which oil can be applied to the gear box 30 and which is connected in terms of drive to the gear box 30. Here, the support structure 24 is configured with a receiving region 47 for the pump unit 46, into which receiving region 47 the pump unit 46 can be introduced from a region outside the interior space 40 via an opening 48 of the support structure 24 and from which receiving region 47 the pump unit 46 can be removed via the opening 48. The pump unit 46 is fixedly connected to the support structure 24, for example by means of screw connections or the like.

[0085] In the exemplary embodiments of the gas turbine engine 10 illustrated in FIG. 4 and FIG. 5, the pump unit 46 protrudes in each case into the interior space 40 from the region outside the interior space 40 through the opening 48 of the support structure 24. In these two exemplary embodiments of the gas turbine engine 10, the receiving region 47 is in each case arranged entirely outside the interior space 40. In addition, in the gas turbine engine 10 as per FIG. 4, the pump unit 46, the receiving region 47 and the opening 48 are provided in a region 24A of the support structure 24 facing toward the fan 23.

[0086] Proceeding from that region 24A of the support structure 24 which faces toward the fan 23 in the direction of a region 24C of the support structure 24 facing toward the compressor 14, a radial spacing R24B between a wall region 24B of the support structure 24 and the main axis of rotation 9 of the gas turbine engine 10 initially increases up to a maximum R24Bmax. The radial spacing R24B then decreases again. The maximum R24Bmax of the radial spacing R24B is provided at least approximately above that region of the gas turbine engine 10 between the fan 24 and the low-pressure compressor 14 in which the gear box 30 is arranged. It is thus achieved in a simple manner that, as the components of the gear box 30 rotate, oil sprayed therefrom is captured and collected in the radially outer region 45 of the support structure 24 with little effort.

[0087] A sealing unit 50 is provided in each case between a casing 49 of the pump unit 46 and the support structure 24 in the region of the opening 48 in order to prevent an undesired escape of oil via the opening 48.

[0088] A drive shaft 51 of the pump unit 46 according to FIG. 4 and according to FIG. 5 is connected in terms of drive to the planet carrier 34 via a gear box unit 52. The gear box unit 52 according to FIG. 4 comprises a first spur gear 53 which is connected to the drive shaft 51 of the pump unit 46. The spur gear 53 meshes with a further spur gear 54 which is rotatably mounted in the support structure 24A and which meshes with a spur gear region 55 of the planet carrier 34.

[0089] In general, in all of the embodiments of the gas turbine engine 10 illustrated in the drawing, the pump unit 46 delivers oil to regions of the gear box 30 that are not illustrated in any more detail, which may be rolling bearings or plain bearings of the planet gears 32 and further regions of the gear box 30, irrespective of the direction of rotation of the drive shaft 51 of the pump unit 46.

[0090] The arrangement of the pump unit 46 shown in FIG. 4 offers the possibility of the pump unit 46 being driven, and supplying oil to the gear box 30, as a result of a rotation of the fan 23 even if the gas turbine engine 10 is in a shut-down state and no drive torque is being imparted to the gear box 30 by the low-pressure compressor 14. Furthermore, the pump unit 46 can also be driven by the fan 23 if, in the event of damage, no torque can be introduced into the gear box 30 via the compressor shaft 26 or the sun gear 28. The gear box 30 can thus be supplied with oil by means of the pump unit 46 over a large operating range of the gas turbine engine 10. In addition, the arrangement of the pump unit 46 shown in FIG. 4 offers the possibility of the pump unit 46 being exchanged or replaced with little effort during maintenance, with the fan 23 having been uninstalled.

[0091] By contrast to this, in the exemplary embodiments of the gas turbine engine 10 shown in FIG. 5 and FIG. 6, the pump unit 46 is provided in a region 24C of the support structure 24 which faces toward the low-pressure compressor 14. In the exemplary embodiment of the gas turbine engine 10 shown in FIG. 5, the pump unit 46 protrudes into the interior space 40 of the support structure 24, whereas the pump unit 46 according to FIG. 6 is arranged virtually entirely outside the interior space 40, in the receiving region 47.

[0092] The drive shaft 51 of the pump unit 46 according to FIG. 5 is in turn connected rotationally conjointly to the spur gear 53, which is arranged entirely in the interior space 40 and is illustrated as having been pivoted together with the pump unit 46 into the plane of the drawing and which meshes directly with a spur gear region 56 of the planet carrier 34 and which is mounted in the support structure 24 in a manner not illustrated in any more detail.

[0093] By contrast to this, in the exemplary embodiment of the gas turbine engine 10 according to FIG. 6, the spur gear 53 of the gear box unit 52, which is likewise mounted rotatably in the support structure 24 and arranged entirely in the interior space and illustrated as having been pivoted together with the pump unit into the plane of the drawing, meshes with a spur gear region 57 of the compressor shaft 26.

[0094] The arrangement of the pump unit 46 according to FIG. 5 and FIG. 6 offers the possibility of performing maintenance on the pump unit 46 with the low-pressure compressor 14 having been uninstalled and optionally without uninstalling the spur gear 53. In addition, the likelihood of the pump unit 46 of the gas turbine engine 10 according to FIG. 5 or according to FIG. 6 being damaged as a result of a blade breakage in the region of the fan 23 is lower than that in the case of the embodiment of the gas turbine engine 10 according to FIG. 4.

[0095] The connection of the pump unit 46 to the compressor shaft 26 in terms of drive in turn offers the possibility of operating the pump unit 46 at higher drive rotational speeds and of dimensioning the pump unit 46 to be smaller in relation to the connection to the planet carrier 34 or to the fan shaft 36.

[0096] FIG. 7 and FIG. 8 each show a three-dimensional partial view of the support structure 24 and of the pump unit 46. The pump unit 46 is illustrated in FIG. 7 in the uninstalled state and in FIG. 8 in the installed operating state.

[0097] In general, provision may be made for a suction side of the pump unit 46 to be directly connected to the radially outer region 45 and to draw oil in from there. It is furthermore also possible for the pump unit 46 to be connected to an oil reservoir, which may be arranged within the interior space 40, within and outside the interior space 40 or outside the interior space 40, or to be connectable to such an oil reservoir. It is possible here for the oil reservoir to be provided in the radially outer region 45 or for oil that has collected in the radially outer region 45 to be introduced into such an oil reservoir. In addition, the pump unit may also deliver oil directly from the radially outer region 45 and from such an oil reservoir, or from other oil reservoirs of the gas turbine engine 10, in the direction of the gear box 30 in order to reliably avoid a deficiency of supply to the gear box 30.

[0098] FIG. 9 shows a first embodiment of an oil system 70 of the gas turbine engine 10. The oil system 70 comprises a first oil circuit 71 and a second oil circuit 72. The first oil circuit 71 and the second oil circuit 72 are fluidically coupled to a common outlet 59 of the gear box 30. Furthermore, the first oil circuit 71 and the second oil circuit 72 are respectively fluidically coupled to a separate inlet 60 and 61 of the gear box 30. The first oil circuit 71 and the second oil circuit 72 are each configured with a pump 62, 63. It is possible here for the pump 62, the pump 63 or both pumps 62 and 63 to correspond to the pump unit 46.

[0099] The outlet 59 of the gear box 30 comprises a device 64 which is designed in such a way that oil from the gear box 30 is introduced into the first oil circuit 71 and into the second oil circuit 72.

LIST OF REFERENCE SIGNS

[0100] 9 Main axis of rotation [0101] 10 Gas turbine engine [0102] 11 Core [0103] 12 Air inlet [0104] 13 Oil volume [0105] 14 Low-pressure compressor [0106] 15 High-pressure compressor [0107] 16 Combustion device [0108] 17 High-pressure turbine [0109] 18 Bypass thrust nozzle [0110] 19 Low-pressure turbine [0111] 20 Core thrust nozzle [0112] 21 Engine nacelle [0113] 22 Bypass duct [0114] 23 Thrust fan [0115] 24 Support structure [0116] 24A Region of the support structure [0117] 24B Wall region of the support structure [0118] 24C Region of the support structure [0119] 26 Shaft, connecting shaft [0120] 27 Connecting shaft [0121] 28 Sun gear [0122] 29 Carrier element [0123] 30 Gear box, planetary gear box [0124] 32 Planet gear [0125] 34 Planet carrier [0126] 36 Linkage [0127] 38 Ring gear [0128] 40 Interior space [0129] 41 to 44 Bearings [0130] 45 Radially outer region of the support structure [0131] 46 Pump unit [0132] 47 Receiving region [0133] 48 Opening [0134] 49 Housing of the pump unit [0135] 50 Sealing unit [0136] 51 Drive shaft [0137] 52 Gear box unit [0138] 53 Spur gear [0139] 54 Further spur gear [0140] 55 to 57 Spur gear region [0141] 59 Outlet [0142] 60, 61 Inlet [0143] 62, 63 Pump [0144] 64 Device [0145] 70 Oil system [0146] 71 First oil circuit [0147] 72 Second oil circuit [0148] A Core air flow [0149] B Bypass air flow [0150] R24B Radial spacing [0151] R24Bmax Maximum of the radial spacing [0152] U Circumferential direction [0153] X Axial direction [0154] Y Radial direction