Aircraft engines and unmanned aerial vehicles

Abstract

This invention provides a structure that stably supports the tail cone of an aircraft engine while reducing the required strength for the tail cone. [Solution] The aircraft engine comprises a turbine, a case housing the turbine, a tail cone positioned downstream of the turbine and tapering toward the rear, which guides the exhaust gas flowing out of the turbine, a reinforcing member partially attached to the tail cone, and a bracket connecting the tail cone to the case.

Description

Technical Field

[0001] The present disclosure relates to aircraft engines and unmanned aircraft.

Background Art

[0002] Patent Document 1 discloses an aircraft engine which is a gas turbine engine. In an aircraft engine, a compressor, a combustor, and a turbine are arranged in this order from the front to the rear. Downstream of the turbine, a tail cone for guiding the exhaust gas flowing out from the turbine is arranged.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the main purpose of the tail cone is to guide the exhaust gas flowing out from the turbine, it is desired to have as simple a structure as possible. However, since the external force received by the tail cone from the exhaust gas is not small, it is required to appropriately support the tail cone.

[0005] One aspect of the present disclosure aims to provide a structure that stably supports a tail cone while reducing the required strength for the tail cone of an aircraft engine.

Means for Solving the Problems

[0006] An aircraft engine according to one aspect of the present disclosure includes a compressor, a combustor through which compressed air from the compressor is introduced, a turbine through which combustion gas from the combustor passes, a rotating shaft connecting the compressor to the turbine, a case housing the turbine, a tail cone located downstream of the turbine and tapering toward the rear, which guides exhaust gas flowing out from the turbine, a reinforcing member partially attached to the tail cone, and a bracket connecting the tail cone to the case. [Effects of the Invention]

[0007] According to one aspect of this disclosure, the tail cone can be stably supported while reducing the required strength for the tail cone. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic cross-sectional view of an aircraft engine according to an embodiment. [Figure 2] Figure 2 is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] Figure 3 is a cross-sectional view taken along line III-III in Figure 2. [Figure 4] Figure 4 is a cross-sectional view taken along line IV-IV in Figure 2. [Figure 5] Figure 5 is a perspective view of an aircraft equipped with the engine shown in Figure 1. [Modes for carrying out the invention]

[0009] The embodiments will be described below with reference to the drawings. In the following description, the axial direction X means the direction in which the axis L of the rotation axis 2 of the aircraft engine 1 extends, the radial direction Y means the direction perpendicular to the axis L, and the circumferential direction Z means the direction extending circumferentially around the axis L. Furthermore, the axial direction X is the front-rear direction of the aircraft engine 1. "Front" means the side of the aircraft engine 1 in the axial direction X from which air is introduced from the outside, and "rear" means the side of the aircraft engine 1 in the axial direction X from which exhaust gas is discharged.

[0010] Figure 1 is a schematic cross-sectional view of an aircraft engine 1 according to an embodiment. The aircraft engine 1 is used as an engine for an aircraft such as an unmanned aerial vehicle. As shown in Figure 1, the aircraft engine 1 is, for example, a turbofan engine. The aircraft engine 1 comprises a rotating shaft 2, a fan 3, a compressor 4, a combustor 5, a turbine 6, and a casing 7. The direction in which the axis L of the rotating shaft 2 extends is referred to as the axial direction X. The fan 3 is connected to the front of the rotating shaft 2 and rotates together with the rotating shaft 2. The compressor 4, combustor 5, and turbine 6 are arranged in this order from front to rear along the rotating shaft 2. The casing 7 houses all or part of the rotating shaft 2, fan 3, compressor 4, combustor 5, and turbine 6.

[0011] The aircraft engine 1 is, for example, a twin-shaft gas turbine engine. The rotating shaft 2 includes a low-pressure shaft 12 and a high-pressure shaft 11 that is coaxial with the low-pressure shaft 12 and rotatable relative to the low-pressure shaft 12. The high-pressure shaft 11 is a tubular hollow shaft. The low-pressure shaft 12 is inserted through the hollow space of the high-pressure shaft 11. The low-pressure shaft 12 is longer than the high-pressure shaft 11 in the front-rear direction, and the front and rear ends of the low-pressure shaft 12 are exposed to the outside of the high-pressure shaft 11. The low-pressure shaft 12 is connected to a fan 3.

[0012] The compressor 4 includes a low-pressure compressor 13 and a high-pressure compressor 14 located behind the low-pressure compressor 13. The low-pressure compressor 13 is an axial-flow compressor, and the high-pressure compressor 14 is a centrifugal compressor. A diffuser 8 is located on the outer circumference of the high-pressure compressor 14 to send the air flowing out of the high-pressure compressor 14 to the rear. A combustor 5 is located behind the diffuser 8. The combustor 5 is a back-flow combustor. The turbine 6 includes a high-pressure turbine 15 and a low-pressure turbine 16 located behind the high-pressure turbine 15. The low-pressure shaft 12 mechanically connects the low-pressure compressor 13 to the low-pressure turbine 16. The high-pressure shaft 11 mechanically connects the high-pressure compressor 14 to the high-pressure turbine 15.

[0013] The casing 7 includes a cylindrical inner shell 17 and an outer shell 18 arranged concentrically with respect to each other. The inner shell 17 houses the compressor 4, the combustor 5, and the turbine 6. A cylindrical bypass passage B is formed between the inner shell 17 and the outer shell 18. A portion of the air drawn in by the fan 3 flows through the bypass passage B and is discharged to the rear. The remaining air drawn in by the fan 3 flows into the low-pressure compressor 13. The air compressed by the low-pressure compressor 13 and the high-pressure compressor 14 flows into the combustor 5 via the diffuser 8. The combustion gases that flow out from the outlet of the combustor 5 pass through the nozzle unit 9, then through the high-pressure turbine 15 and the low-pressure turbine 16, and are discharged to the rear.

[0014] The aircraft engine 1 includes a tail cone 20 located downstream of the low-pressure turbine 16. The tail cone 20 has a substantially conical shape that tapers towards the rear. A substantially conical shape means a shape in which the cross section perpendicular to the axis L at any position in the axial direction X is circular and tapers towards the rear, and includes not only a perfect cone shape in which the outer surface extends linearly in the axial direction X, but also a shape in which the outer surface extends curvedly in the axial direction X.

[0015] The tail cone 20 is hollow. Specifically, the tail cone 20 includes an internal space S, a front opening 20c that opens the internal space S forward, a front end portion 20a that defines the front opening 20c, and a tapered portion 20b that extends backward from the front end portion 20a in a narrowing shape. The tail cone 20 guides the exhaust gas flowing out from the low-pressure turbine 16 from the inside in the radial direction Y. An exhaust gas flow path R is defined between the case 17a that constitutes the inner shell 17 and the tail cone 20. The inner shell 17 may be composed of multiple cases.

[0016] A reinforcing member 21 is partially attached to the tail cone 20. Specifically, an annular reinforcing member 21 is attached to the front end 20a of the tail cone 20. The front end 20a of the tail cone 20 is connected to a plurality of brackets 22 via the reinforcing member 21. The brackets 22 are connected to the case 17a. In other words, the tail cone 20 is supported by the case 17a via the reinforcing member 21 and the brackets 22.

[0017] The material of the tail cone 20 has a lower strength than the materials of the reinforcing member 21 and the bracket 22. The tail cone 20 may have a lower strength than the reinforcing member 21 and the bracket 22 at least during the time from takeoff to landing. The material of the tail cone 20 is, for example, stainless steel, and the materials of the reinforcing member 21 and the bracket 22 are, for example, nickel alloys.

[0018] FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1. As shown in FIG. 2, the front end portion 20a of the tail cone 20 has a circular shape when viewed in the axial direction X. The reinforcing member 21 has a circular shape when viewed in the axial direction X. The reinforcing member 21 is arranged so as to extend in the circumferential direction Z of the tail cone 20 along the circular front end portion 20a of the tail cone 20. The reinforcing member 21 is fixed to the front end portion 20a of the tail cone 20 by a first fastener 31. The reinforcing member 21 reinforces the front end portion 20a of the tail cone 20.

[0019] The bracket 22 includes a first attachment portion 22a, a second attachment portion 22b, and a connecting portion 22c. The bracket 22 is, for example, a plate. The first attachment portion 22a is arranged along the outer peripheral surface of the front end portion 20a of the tail cone 20 and is fixed to the reinforcing member 21 by a second fastener 32. The second attachment portion 22b is arranged along the inner peripheral surface of the case 17a and is fixed to the case 17a by a third fastener 33.

[0020] The connecting portion 22c connects the first attachment portion 22a to the second attachment portion 22b. The connecting portion 22c crosses the exhaust gas flow path R. The connecting portion 22c extends in a direction inclined at a predetermined inclination angle θ with respect to the radial direction Y of the tail cone 20. The inclination angle θ can be, for example, a value of 30 degrees or more and 90 degrees or less.

[0021] The connecting portion 22c is adjacent to one side in the circumferential direction Z with respect to the first attachment portion 22a, and the second attachment portion 22b is adjacent to the one side in the circumferential direction Z with respect to the connecting portion 22c. The plurality of brackets 22 are arranged point-symmetrically about the axis L when viewed in the axial direction X.

[0022] Since the connecting portion 22c is inclined with respect to the radial direction Y of the tail cone 20, the bracket 22 supports the tail cone 20 more flexibly and the stress generated in the bracket 22 due to thermal expansion is reduced as compared with the case where the connecting portion 22c extends in the radial direction Y without being inclined with respect to the radial direction Y of the tail cone 20.

[0023] The plate thickness T of the connecting portion 22c as viewed from the axial direction X shown in FIG. 2 is smaller than the width W of the connecting portion 22c shown in FIG. 4. That is, the main surface of the plate-like connecting portion 22c of the bracket extends along the axial direction X. Thereby, the bracket 22 can support the tail cone 20 more flexibly and prevent the bracket 22 from obstructing the smooth passage of the exhaust gas.

[0024] FIG. 3 is a sectional view taken along line III-III of FIG. 2. As shown in FIG. 3, the front end portion 20a of the tail cone 20 has a cylindrical shape parallel to the axial direction X. The tapered portion 20b of the tail cone 20 extends rearward in the axial direction X from the rear end of the front end portion 20a and has a substantially conical shape that tapers rearward.

[0025] The reinforcing member 21 includes a circumferential plate portion 21a, a protruding plate portion 21b, and a rib portion 21c. The circumferential plate portion 21a is disposed along the outer peripheral surface of the front end portion 20a of the tail cone 20. The circumferential plate portion 21a has a cylindrical shape parallel to the axial direction X. The inner peripheral surface of the circumferential plate portion 21a is in surface contact with the outer peripheral surface of the front end portion 20a of the tail cone 20. The circumferential plate portion 21a extends in the circumferential direction Z at the front end portion 20a of the tail cone 20. The circumferential plate portion 21a is fixed to the front end portion 20a of the tail cone 20 by a plurality of first fasteners 31. The first fastener 31 is, for example, a rivet.

[0026] The front end portion 20a of the tail cone 20 has a plurality of fastening holes H1 spaced apart in the circumferential direction Z. The circumferential plate portion 21a has a plurality of first fastening holes H2 that each match the plurality of fastening holes H1 of the tail cone 20. The reinforcing member 21 is fixed to the front end portion 20a of the tail cone 20 by a first fastener 31 that passes through both the fastening holes H1 of the tail cone 20 and the first fastening holes H2 of the reinforcing member 21. The first fastener 31 is positioned on the portion of the circumferential plate portion 21a of the reinforcing member 21 that avoids the first mounting portion 22a of the bracket 22. The circumferential plate portion 21a of the reinforcing member 21 increases the strength of the front end portion 20a of the tail cone 20.

[0027] The protruding plate portion 21b protrudes inward from the front end of the circumferential plate portion 21a in the radial direction Y of the tail cone 20. As shown in Figure 2, the protruding plate portion 21b has an annular shape that extends in the circumferential direction Z when viewed from the axial direction X. The protruding plate portion 21b maintains the circular shape of the circumferential plate portion 21a when viewed from the axial direction X, even when the tail cone 20 is subjected to uneven external forces from the exhaust gas, thereby maintaining the circular shape of the front end portion 20a of the tail cone 20.

[0028] The rib portion 21c protrudes from the inner end of the protruding plate portion 21b in the radial direction Y toward the rear in the axial direction X. The length of the rib portion 21c in the axial direction X is shorter than the length of the circumferential plate portion 21a in the axial direction X. The rib portion 21c prevents deformation of the protruding plate portion 21b, and as a result, deformation of the circumferential plate portion 21a is also prevented.

[0029] Figure 4 is a cross-sectional view taken along line IV-IV in Figure 2. As shown in Figure 4, the first mounting portion 22a of the bracket 22 is superimposed on a part of the outer circumferential surface of the circumferential plate portion 21a of the reinforcing member 21. In this embodiment, the plate thickness of the bracket 22 is greater than, but not limited to, the plate thickness of the reinforcing member 21. The circumferential plate portion 21a of the reinforcing member 21 has a plurality of second fastening holes H3. The first mounting portion 22a of each bracket 22 has a plurality of fastening holes H4 that correspond to the plurality of second fastening holes H3 of the reinforcing member 21. The first mounting portion 22a of the bracket 22 is fixed to the circumferential plate portion 21a of the reinforcing member 21 by a second fastener 32 that passes through both the fastening holes H4 of the bracket 22 and the second fastening holes H3 of the reinforcing member 21.

[0030] The second fastener 32 is, for example, a rivet. The second fastening hole H3 of the reinforcing member 21 faces the notch C of the front end 20a of the tail cone 20 in the radial direction Y. The second fastener 32 is positioned at the notch C of the tail cone 20 so as to avoid the tail cone 20. This allows each component 20, 21, and 22 to be fixed to each other more stably than when the tail cone 20, reinforcing member 21, and bracket 22 are fastened together by the second fastener 32.

[0031] Figure 5 is a perspective view of the unmanned aerial vehicle 100 equipped with the engine 1 shown in Figure 1. As shown in Figure 5, the unmanned aerial vehicle 100 is, for example, an autonomously flying aircraft. The engine 1 is located, for example, inside a through-hole 101a that is located in the fuselage 101 of the unmanned aerial vehicle 100 and extends in the longitudinal direction. The configuration of the unmanned aerial vehicle 100 and the arrangement of the engine 1 in the aircraft 100 are not limited to this.

[0032] As described above, the reinforcing member 21 reinforces the circular front end 20a of the tail cone 20, making it easier for the tail cone 20 to maintain its conical shape even when subjected to external forces from exhaust gases. Furthermore, since the reinforced front end 20a of the tail cone 20 is supported by the bracket 22 and the reinforcing member 21 bears the load from the bracket 22, the support strength of the tail cone 20 is also improved. Therefore, the tail cone 20 can be stably supported while reducing the required strength for the tail cone 20.

[0033] The technology of this disclosure is not limited to the embodiments described above. For example, the reinforcing member may be attached to the central part of the tail cone in the front-rear direction instead of the front end of the tail cone. The protruding plate portion 21b may protrude outward in the radial direction Y from the circumferential plate portion 21a. The rib portion 21c may be omitted in the reinforcing member 21. The protruding plate portion 21b may also be omitted in the reinforcing member 21. The circumferential plate portion 21a may be arranged along the inner circumferential surface of the tail cone 20. The rib portion 21c may protrude forward in the axial direction X from the protruding plate portion 21b. The bracket 22 is not limited to a plate shape and may have a shape including, for example, a rod or a rectangular prism, or may be a combination of multiple members.

[0034] As described above, the embodiments have been explained as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited to the embodiments described above and can be applied to embodiments that have been modified, replaced, added, or omitted as appropriate. Furthermore, it is possible to combine the components described in the embodiments to create new embodiments. For example, some components in an embodiment can be separated from other components in that embodiment and extracted at will. In addition, the components described in the attached drawings and detailed description include not only components that are essential for solving the problem, but also components that are not essential for solving the problem, in order to illustrate the technology.

[0035] [Pattern] The embodiments described above are specific examples of the following embodiments.

[0036] (Aspect 1) Compressor and, A combustor into which compressed air from the aforementioned compressor is introduced, A turbine through which the combustion gas from the aforementioned combustor passes, The compressor is connected to the turbine by a rotating shaft, A case for housing the turbine, A tail cone is positioned downstream of the turbine, has a shape that tapers towards the rear, and guides the exhaust gas flowing out of the turbine. A reinforcing member partially attached to the tail cone, An aircraft engine comprising a bracket for connecting the tail cone to the case.

[0037] According to Embodiment 1, since the tail cone is reinforced by the reinforcing member, the shape of the tail cone is more easily maintained even when it is subjected to external forces from exhaust gas. Therefore, the tail cone can be stably supported while reducing the required strength for the tail cone.

[0038] (Aspect 2) The aircraft engine according to embodiment 1, wherein the reinforcing member is arranged along the circumferential surface of the tail cone and has an annular shape extending in the circumferential direction of the tail cone.

[0039] According to embodiment 2, the shape of the circumferential surface of the tail cone can be maintained in good condition.

[0040] (Aspect 3) The tail cone includes an internal space, a front opening that opens the internal space forward, and a front end that defines the front opening. The reinforcing member is attached to the front end of the tail cone so as to extend along the front end of the tail cone in the circumferential direction of the tail cone, The aircraft engine according to embodiment 1 or 2, wherein the bracket connects the front end of the tail cone to the case.

[0041] According to embodiment 3, the reinforced front end of the tail cone is supported by a bracket, and the reinforcing member bears the load from the bracket, thereby improving the support strength of the hollow tail cone.

[0042] (Aspect 4) The aircraft engine according to any one of embodiments 1 to 3, wherein the bracket is fixed to the reinforcing member by fasteners.

[0043] According to embodiment 4, the bracket is indirectly connected to the tail cone via a reinforcing member. As a result, the reinforcing member directly bears the load from both the bracket and the tail cone, thereby improving the support stability of the tail cone.

[0044] (Aspect 5) The reinforcing member is A circumferential plate portion arranged along the circumferential surface of the tail cone, An aircraft engine according to any one of embodiments 1 to 4, comprising a protruding plate portion that protrudes radially from the circumferential plate portion in the direction of the tail cone.

[0045] According to embodiment 5, the strength of the tail cone is increased by the circumferential plate portion of the reinforcing member. Furthermore, even if the tail cone is subjected to uneven external forces from the exhaust gas, the shape of the tail cone can be maintained by the protruding plate portion of the reinforcing member.

[0046] (Aspect 6) The aforementioned bracket is A first mounting portion attached to the reinforcing member, A second mounting portion attached to the aforementioned case, An aircraft engine according to any one of embodiments 1 to 5, comprising: a connecting portion extending in a direction inclined with respect to the radial direction of the tail cone and connecting the first mounting portion to the second mounting portion.

[0047] According to embodiment 6, compared to the case where the connecting portion of the bracket extends in the radial direction of the tail cone, the bracket can flexibly support the tail cone, thereby reducing the stress generated in the bracket due to thermal expansion.

[0048] (Aspect 7) A first fastener for fixing the reinforcing member to the tail cone, An aircraft engine according to any one of embodiments 1 to 6, further comprising: a second fastener positioned to avoid the tail cone and for fixing the bracket to the reinforcing member.

[0049] According to Embodiment 7, these components can be fixed to each other more stably than when the tail cone, reinforcing member, and bracket are fastened together with a fastener.

[0050] (Pattern 8) The tail cone is made of stainless steel, The aircraft engine according to any one of embodiments 1 to 7, wherein the reinforcing member and the bracket are made of nickel alloy.

[0051] According to embodiment 8, the tail cone and its support structure can be made low-cost and high-strength.

[0052] (Aspect 9) An unmanned aerial vehicle equipped with the aircraft engine described in any of embodiments 1 to 8.

[0053] According to embodiment 9, it is possible to provide an unmanned aerial vehicle equipped with an engine that reduces the required strength for the tail cone and stably supports the tail cone. [Explanation of Symbols]

[0054] 1. Aircraft engine 2 rotation axes 4. Compressor 5 Combustor 6 Turbines 17a Case 20 Tail cones 20a Front end 20b Tapered section 20c front opening 21 Reinforcement member 21a Circumferential plate part 21b Projecting plate part 22 brackets 22a First mounting section 22b Second mounting section 22c Connecting part 31 First fastening device 32 Second fastener 100 Unmanned Aircraft C notch H1 fastening hole H2 1st fastening hole H3 2nd fastening hole H4 fastening hole S interior space Y radial direction Z circumferential direction

Claims

1. Compressor and, A combustor into which compressed air from the aforementioned compressor is introduced, A turbine through which the combustion gas from the aforementioned combustor passes, The compressor is connected to the turbine by a rotating shaft, A case for housing the turbine, A tail cone is positioned downstream of the turbine and guides the exhaust gas flowing out of the turbine, A reinforcing member partially attached to the tail cone, The tail cone is connected to the case by a bracket, The reinforcing member is A circumferential plate portion arranged along the circumferential surface of the tail cone, An aircraft engine comprising a protruding plate portion that extends radially from the circumferential plate portion toward the tail cone.

2. The aircraft engine according to claim 1, wherein the reinforcing member is arranged along the circumferential surface of the tail cone and has an annular shape extending in the circumferential direction of the tail cone.

3. The tail cone includes an internal space, a front opening that opens the internal space forward, and a front end that defines the front opening. The reinforcing member is attached to the front end of the tail cone so as to extend along the front end of the tail cone in the circumferential direction of the tail cone, The aircraft engine according to claim 1, wherein the bracket connects the front end of the tail cone to the case.

4. The aircraft engine according to claim 1, wherein the bracket is fixed to the reinforcing member by fasteners.

5. The aforementioned bracket is A first mounting portion attached to the reinforcing member, A second mounting portion attached to the aforementioned case, The aircraft engine according to claim 1, further comprising: a connecting portion extending in a direction inclined with respect to the radial direction of the tail cone, and connecting the first mounting portion to the second mounting portion.

6. A compressor and A combustor into which compressed air from the aforementioned compressor is introduced, A turbine through which the combustion gas from the aforementioned combustor passes, The compressor is connected to the turbine by a rotating shaft, A case for housing the turbine, A tail cone is positioned downstream of the turbine and guides the exhaust gas flowing out of the turbine, A reinforcing member partially attached to the tail cone, A bracket for connecting the tail cone to the case, A first fastener for fixing the reinforcing member to the tail cone, An aircraft engine comprising: a second fastener positioned to avoid the tail cone and for fixing the bracket to the reinforcing member.

7. The tail cone is made of stainless steel, The aircraft engine according to claim 1, wherein the reinforcing member and the bracket are made of nickel alloy.

8. An unmanned aircraft comprising the aircraft engine described in any one of claims 1 to 7.

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