COMPONENT FOR FASTENING ARRANGEMENT, FASTENING ARRANGEMENT AND GAS TURBINE ENGINE COMPRISING FASTENING ARRANGEMENT

Abstract

A component for a fastening arrangement of a gas turbine engine, the component comprising: a first abutment member; a second abutment member; a spring member between the first and second abutment members; a conduit comprising a throughole through the first and second abutment members and the spring member; the component being configured such that a shaft of a fastener passes through the throughole, a head of the fastener abuts the first abutment member and a part to be fastened by the fastening arrangement abuts the second abutment member, when the component is in the fastening arrangement.

Claims

1. A component for a fastening arrangement of a gas turbine engine, the component comprising: a first abutment member; a second abutment member; a spring member between the first and second abutment members; and a conduit comprising a throughole through the first and second abutment members and the spring member; the component being configured such that a shaft of a fastener passes through the throughole, a head of the fastener abuts the first abutment member and a part to be fastened by the fastening arrangement abuts the second abutment member, when the component is in the fastening arrangement.

2. The component of claim 1, wherein the second abutment member and the conduit comprise respective engagement portions configured to engage with each other to prevent rotational displacement between the second abutment member and the conduit about an axis through the throughole.

3. The component of claim 2, wherein the engagement portions comprise respective channels and protrusions.

4. The component of claim 3, wherein the channels are provided in an outer wall of the conduit.

5. The component of claim 2, wherein the engagement portions are configured to engage with each other to allow translational displacement between the second abutment member and the conduit in a direction parallel to the axis through the throughole.

6. The component of claim 2, comprising at least two sets of respective engagement portions.

7. The component of claim 1, wherein the first and second abutment members substantially surround the conduit.

8. The component of claim 1, wherein the conduit is substantially cylindrical in shape.

9. The component of claim 1, wherein the first and/or second abutment members are substantially disc-shaped.

10. The component of claim 1, wherein the conduit extends from the first abutment member.

11. The component of claim 1, wherein the conduit is integrally formed with the first abutment member.

12. The component of claim 1, wherein the second abutment member is connected to the first abutment member by the spring member.

13. The component of claim 1, wherein the first and second abutment members and the spring member are integrally formed.

14. The component of claim 1, wherein the component is formed as one element by an additive manufacturing process.

15. The component of claim 1, wherein the spring member substantially surrounds the walled conduit.

16. The component of claim 1, wherein the spring is configured to provide a spring force in a direction parallel to an axis through the throughole.

17. A fastening arrangement for fastening together first and second parts of gas turbine engine having a throughole therethrough, the fastening arrangement comprising: the component of claim 1, wherein the conduit is arranged with the throughole in the first and second parts and the second abutment member abuts the first part; and a fastener comprising a shaft arranged within the throughole of the conduit and a head abutting the first abutment part.

18. The fastening arrangement of claim 17, further comprising a nut configured to engage with a thread on the shaft of the fastening member, and arranged to abut the second part of the gas turbine engine and tighten the fastening arrangement such that the spring member is compressed between the head of the fastener and the first part of the gas turbine engine.

19. The fastening arrangement of claim 17, further comprising an insert arranged between the first part of the gas turbine engine and at least one of the second abutment member and the conduit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Embodiments will now be described by way of example only, with reference to the Figures, in which:

[0062] FIG. 1 is a sectional side view of a gas turbine engine;

[0063] FIG. 2 is a close up sectional side view of an upstream portion of a gas turbine engine;

[0064] FIG. 3 is a partially cut-away view of a gearbox for a gas turbine engine;

[0065] FIG. 4 is a cut-away view of a fastener arrangement of the disclosure;

[0066] FIG. 5 is a cut-away view of a component for a fastening arrangement of the present disclosure;

[0067] FIG. 6 is an oblique view, from above, of the component of disclosure;

[0068] FIG. 7 is an oblique view, from below, of the component of disclosure;

[0069] FIG. 8 is a side view of the component of the disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0070] Aspects and embodiments of the present disclosure will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art.

[0071] FIG. 1 illustrates a gas turbine engine 10 having a principal rotational axis 9. The engine 10 comprises an air intake 12 and a propulsive 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. The engine core 11 comprises, in axial flow series, a low pressure compressor 14, a high-pressure compressor 15, combustion equipment 16, a high-pressure turbine 17, a low pressure turbine 19 and a core exhaust nozzle 20. A nacelle 21 surrounds the gas turbine engine 10 and defines a bypass duct 22 and a bypass exhaust nozzle 18. The bypass airflow B flows through the bypass duct 22. The fan 23 is attached to and driven by the low pressure turbine 19 via a shaft 26 and an epicyclic gearbox 30.

[0072] In use, the core airflow 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 exhausted from the high pressure compressor 15 is directed into the combustion equipment 16 where it is mixed with fuel and the mixture is combusted. The resultant hot combustion products then expand through, and thereby drive, the high pressure and low pressure turbines 17, 19 before being exhausted through the nozzle 20 to provide some propulsive thrust. The high pressure turbine 17 drives the high pressure compressor 15 by a suitable interconnecting shaft 27. The fan 23 generally provides the majority of the propulsive thrust. The epicyclic gearbox 30 is a reduction gearbox.

[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 wheel, or sun gear, 28 of the epicyclic gear arrangement 30. Radially outwardly of the sun gear 28 and intermeshing therewith is a plurality of planet gears 32 that are coupled together by a planet carrier 34. The planet carrier 34 constrains the planet gears 32 to process around the sun gear 28 in synchronicity whilst enabling each planet gear 32 to rotate about its own axis. The planet carrier 34 is coupled via linkages 36 to the fan 23 in order to drive its rotation about the engine axis 9. Radially outwardly of the planet gears 32 and intermeshing therewith is an annulus or ring gear 38 that is coupled, via linkages 40, to a stationary supporting structure 24.

[0074] Note that the terms low pressure turbineand low pressure compressoras used herein may be taken to mean the lowest pressure turbine stages and lowest pressure compressor stages (i.e. not including the fan 23) respectively and/or the turbine and compressor stages that are connected together by the interconnecting shaft 26 with the lowest rotational speed in the engine (i.e. not including the gearbox output shaft that drives the fan 23). In some literature, the low pressure turbineand low pressure compressorreferred to herein may alternatively be known as the Intermediate pressure turbine and intermediate pressure compressor. Where such alternative nomenclature is used, the fan 23 may be referred to as a first, or lowest pressure, compression stage.

[0075] The epicyclic gearbox 30 is shown by way of example in greater detail in FIG. 3. Each of the sun gear 28, planet gears 32 and ring gear 38 comprise teeth about their periphery to intermesh with the other gears. However, for clarity only exemplary portions of the teeth are illustrated in FIG. 3. There are four planet gears 32 illustrated, although it will be apparent to the skilled reader that more or fewer planet gears 32 may be provided within the scope of the claimed invention. Practical applications of a planetary epicyclic gearbox 30 generally comprise at least three planet gears 32.

[0076] The epicyclic gearbox 30 illustrated by way of example in FIGS. 2 and 3 is of the planetary type, in that the planet carrier 34 is coupled to an output shaft via linkages 36, with the ring gear 38 fixed. However, any other suitable type of epicyclic gearbox 30 may be used. By way of further example, the epicyclic gearbox 30 may be a star arrangement, in which the planet carrier 34 is held fixed, with the ring (or annulus) gear 38 allowed to rotate. In such an arrangement the fan 23 is driven by the ring gear 38. By way of further alternative example, the gearbox 30 may be a differential gearbox in which the ring gear 38 and the planet carrier 34 are both allowed to rotate.

[0077] It will be appreciated that the arrangement shown in FIGS. 2 and 3 is by way of example only, and various alternatives are within the scope of the present disclosure. Purely by way of example, any suitable arrangement may be used for locating the gearbox 30 in the engine 10 and/or for connecting the gearbox 30 to the engine 10. By way of further example, the connections (such as the linkages 36, 40 in the FIG. 2 example) between the gearbox 30 and other parts of the engine 10 (such as the input shaft 26, the output shaft and the fixed structure 24) may have any desired degree of stiffness or flexibility. By way of further example, any suitable arrangement of the bearings between rotating and stationary parts of the engine (for example between the input and output shafts from the gearbox and the fixed structures, such as the gearbox casing) may be used, and the disclosure is not limited to the exemplary arrangement of FIG. 2. For example, where the gearbox 30 has a star arrangement (described above), the skilled person would readily understand that the arrangement of output and support linkages and bearing locations would typically be different to that shown by way of example in FIG. 2.

[0078] Accordingly, the present disclosure extends to a gas turbine engine having any arrangement of gearbox styles (for example star or planetary), support structures, input and output shaft arrangement, and bearing locations.

[0079] Optionally, the gearbox may drive additional and/or alternative components (e.g. the intermediate pressure compressor and/or a booster compressor).

[0080] Other gas turbine engines to which the present disclosure may be applied may have alternative configurations. For example, such engines may have an alternative number of compressors and/or turbines and/or an alternative number of interconnecting shafts. By way of further example, the gas turbine engine shown in FIG. 1 has a split flow nozzle 18, 20 meaning that the flow through the bypass duct 22 has its own nozzle 18 that is separate to and radially outside the core exhaust nozzle 20. However, this is not limiting, and any aspect of the present disclosure may 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) may have a fixed or variable area. Whilst the described example relates to a turbofan engine, the disclosure may apply, for example, to any type of gas turbine engine, such as an open rotor (in which the fan stage is not surrounded by a nacelle) or turboprop engine, for example. In some arrangements, the gas turbine engine 10 may not comprise a gearbox 30.

[0081] The geometry of the gas turbine engine 10, and components thereof, is defined by a conventional axis system, comprising an axial direction (which is aligned with the rotational axis 9), a radial direction (in the bottom-to-top direction in FIG. 1), and a circumferential direction (perpendicular to the page in the FIG. 1 view). The axial, radial and circumferential directions are mutually perpendicular.

[0082] FIG. 4 shows an example fastening arrangement according to the present disclosure. The fastening arrangement is configured to fasten a first part 60 to a second part 60 of the gas turbine engine 10. In the specific example shown, the first part 60 is a heat shield (e.g. a CMC heat shield) and the second part 61 is a bracket of the gearbox 30.

[0083] The first part 60 is fastened to the second part 61 by a fastener 50 (e.g. a bolt) passing through a throughole in the first part 60 and the second part 61. Optionally, a nut 53 and washer 54 may form part of the fastening arrangement. As shown in FIG. 4, a further component 1 is provided between the head 51 of the fastener 50 and the first part 60. Optionally, an insert 70 may be provided between the component 1 and the first part 60.

[0084] Although the fastening arrangement of FIG. 4 is for a heat shield 60 attached to a bracket 61 of the gear box 30, it should be understood that the fastening arrangement disclosed herein could be used for fastening any two parts of the gas turbine engine 10 together.

[0085] As shown in FIG. 4, the component 1 generally comprises a first abutment member 2, a second abutment member 3, a spring member 4 between the first and second abutment members 2, 3 and a conduit 5. The conduit 5 comprises a throughole 6. The conduit is arranged such that the throughhole 6 passes through the first and second abutment members 2, 3.

[0086] The component 1 is configured such that, in the fastening arrangement, the shaft 52 of the fastener 50 passes through the throughole 6 of the conduit 5. Further, the head 51 of the fastener abuts the first abutment member 2. The second abutment member 3 is configured to abut the first part 60 to be fastened by the fastening arrangement.

[0087] Accordingly, the first and second abutment members 2, 3 and spring member 4 are sandwiched between the head 51 of the fastener 50 and the first part 60. Further, the conduit 5 is arranged within the throughole in first part 60.

[0088] In the fastening arrangement, a threaded nut 53 (and optional washer 54) may be configured to engage with a thread on the shaft 52 of the fastening member 50. The nut 53 may be arranged to abut the second part 61 of the gas turbine engine 10 and tighten the fastening arrangement such that the spring member 4 is compressed between the head 51 of the fastener 50 and the first part 60 of the gas turbine engine 10.

[0089] FIG. 5 is a more detailed cut-out view of the component 1. It can be seen from the arrows in this Figure that the load from the fastener 50 is transmitted via the first abutment member 2 and the conduit 5. The second abutment member 3 and spring member 4 may be compressed (e.g. by thermal expansion) by the first and or second parts 60, 61 being fastened by the fastening arrangement. Accordingly, the spring member 4 may exert an opposing spring force via the first and second abutment members 2, 3.

[0090] In the example shown in the Figures, it can be seen that the second abutment member 3 and spring member 4 are configured to move independently of the first abutment member 2 and conduit 5, at least in a direction parallel to an axis through the throughole 6. Accordingly, the second abutment member 3 and spring member 4 may not be fixedly connected to the conduit 5.

[0091] On the other hand, the first abutment member 2 and the conduit 5 may be fixedly connected to each other. For example, as shown in FIG. 5, the conduit 5 may extend from the first abutment member 2. In some examples, such as that shown in the figures, the conduit 5 may be integrally formed with the first abutment member 2.

[0092] The second abutment member 3 may be connected to the first abutment member 2 by the spring member 4. In some examples, the first and second abutment members 2, 3 and the spring member 4 may be integrally formed with each other. For example, the component 1 may be made as a single element by an additive manufacturing process.

[0093] As shown in FIG. 6, the first and second abutment members 2, 3 may substantially surround the conduit 5. As shown, the conduit 5 may be substantially cylindrical in shape. Further, the first and or second abutment members may be substantially disc-shaped. The component 1 may have substantially cylindrical symmetry about the central axis through the throughhole 6.

[0094] Regardless of the specific shapes of the first and second abutment members 2, 3, an outer surface of the first abutment member 2 and an outer surface of the second abutment member 3 are preferably substantially planar. The outer surfaces in this context are those facing away from the spring member 4, and in a direction substantially parallel to the central axis through the throughhole 6.

[0095] The spring member 4 is not limited to any particular type of spring. However, as shown in FIG. 6, the spring member 4 may comprise one or more wave springs. The spring member 4 may be configured to exert a spring force in a direction from the first abutment member 2 to the second abutment member 3. In other words, the spring member 4 provides a spring force in a direction parallel to a central axis through the throughole 6.

[0096] As shown in FIG. 6, the spring member 4 may also substantially surround the conduit 5.

[0097] As shown in FIG. 7, the second abutment member 3 and the conduit 5 may comprise respective engagement portions 7, 8 configured to engage with each other to prevent rotational displacement between the second abutment member 2 and the conduit 5 about an axis through the throughole 6. As shown, the engagement portions of the conduit 5 may be channels 8 and the engagement portions of the second abutment member 3 may be corresponding protrusions 7. However, the converse arrangement is also possible. The protrusion 7 are configured to extend into the channels 8 in a direction oblique to (e.g. perpendicular to) an axis through the throughole 6.

[0098] The engagement portions 7, 8 may be configured to engage with each other to allow translational displacement between the second abutment member 3 and the conduit 5 in a direction parallel to an axis passing through the throughhole 6. In the example shown in FIG. 8, channels 8 extend in an axial direction of the conduit 5 (i.e. parallel to an axis through the throughhole 6) to allow protrusions 7 of the second abutment member 3 to move up and down the channel 8, while remaining engaged with the channel 8.

[0099] Any number of sets of respective engagement portions may be provided. However, preferably at least two sets of respective engagement portions are provided on the second abutment member 3 and conduit 5. For example, three sets of respective engagement portions 7, 8 are provided in the example component 1 shown in FIGS. 7 and 8.

[0100] The component 1 described above may allow for thermal expansion of the of the first and second parts 60, 61 of the gas turbine engine 10. The component 1 may also provide damping of vibrations through the first and second parts 60, 61 of the gas turbine engine 10.

[0101] The materials from which the component 1 is formed may be any material having properties suitable for the load conditions, weight constraints and environment (e.g. temperature) in which the component 1 is to be used. For example the material may comprise one or more of: steel and its alloys, aluminium and its alloys, titanium and its alloys, nickel and its alloys, copper and its alloys, polymers, metal coated polymers, and composite materials. It should be understood that this list is not exhaustive.

[0102] As shown in FIG. 4, in the fastening arrangement, an insert 70 may be provided between the component 1 and the first part 60 of the gas turbine engine 10. The insert may be provided specifically between the first part 60 and second abutment member 3 and/or between the first part 60 and the conduit 5. Optionally, the insert may also be provided between the first part 60 and the second part 61 of the gas turbine engine.

[0103] The insert 60 may comprise a low friction surface. This surface may allow sliding displacement between the component 1 and the first part, e.g. allowing for thermal expansion.

[0104] As shown in FIG. 4, the insert may be configured to substantially surround the conduit 6. The insert may comprise a disc-shaped portion arranged on a first (e.g. top) surface of the first part 60 adjacent the second abutment member 3. A substantially cylindrical-shaped portion of the insert 70 may line the throughole in the first part 60 and be arranged adjacent the conduit 5. A further disc-shaped portion of the insert 70 may be provided on a second (e.g. bottom) surface of the first part 60 adjacent the second part 61.

[0105] The portion of the insert adjacent the conduit 5 may comprise one or more slots 71 allowing for thermal expansion of the insert 70. The slots 71 may extend in a circumferential direction of the insert 70.

[0106] The insert may be formed from a metal substrate. The metal substrate may be coated with a low friction material such as a ceramic or lubricant.

[0107] It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.