Aeroengine accessory drive system

Abstract

The application aims to provide an aero-engine accessory drive system, which comprises a drive gear box, an accessory and a sealing assembly. The drive gear box has a first drive shaft, the accessory has a second drive shaft, and the second drive shaft is in driving connection with the first drive shaft. The sealing assembly has a matching part, the sealing assembly is in matching connection with the first drive shaft or the second drive shaft through the matching part, and the sealing assembly is clamped between the first drive shaft and the second drive shaft. At least a part of the sealing assembly is made of a shape memory alloy, so that the sealing assembly is deformed radially to be in interference fit with the second drive shaft in a high-temperature state. The aero-engine accessory drive system can meet the fireproof requirement and is easy to realize.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of gas turbine engine, in particular to an aero-engine accessory drive system. BACKGROUND

[0002] The gas turbine engine is the most widely used aero-engine at present, and is known as one of the "pearls on the crown of industry". During the operation of the aero-engine, it not only provides power for the aircraft, but also outputs power to drive the accessory drive mechanism of the engine, and then drives various electrical equipment carried on the aircraft. Conversely, during the starting stage, the starter in the accessory drives the engine through the gear shaft of the accessory drive gear box in the reverse direction to output power, drives the engine, and then takes off the aircraft. The accessory drive mechanism and various accessories use gear meshing to transmit power, and the gear meshing, bearing, spline and other positions need to be cooled and lubricated by oil. Therefore, it is inevitable to use more rubber rings for oil sealing in the accessory drive system.

[0003] At present, civil aviation airworthiness regulations at home and abroad have requirements for engine fire prevention. As an oil delivery component, the accessory drive mechanism should be fireproof, i.e. the ability to withstand an average flame temperature of 1100℃ (about 2000℉) for at least 15 minutes while maintaining the original function or structural integrity when the component is exposed to a hot field or other specific environment. However, the commonly used rubber ring in the accessory drive mechanism will creep, age and carbonize under such high temperature conditions, resulting in sealing failure and oil leakage, thereby causing the fire area to expand. Therefore, in order to meet the fireproofing requirements, it is urgent to solve the problem of oil leakage caused by aging of the rubber ring at ultra-high temperature.

[0004] To solve the above problems, there are two solutions at present:

[0005] One is to study new elastic materials, so that the sealing ring can withstand a flame temperature above the heat resistance, thereby ensuring that the sealing ring is reliable under ultra-high temperature. And in the normal working state, the sealing ring can still realize the established sealing function.

[0006] The second is to precisely design the sealing shaft hole cooperation, to reduce the gap between the shaft holes as much as possible, so that the rubber ring can still ensure small oil leakage in case of failure.

[0007] However, the selected technical route in the first solution has a long research and development cycle and high research and development cost, which violates the economic requirements of civil aviation; the selected technical route in the second solution requires high processing precision and design personnel, which is prone to difficult assembly of shaft hole cooperation and collision during operation, and greatly increases the processing cost. SUMMARY

[0008] The present application aims to provide an aero-engine accessory drive system which can meet the fireproof requirement and is easy to implement.

[0009] To achieve the aforementioned purpose, the aero-engine accessory drive system comprises:

[0010] a transmission gear box having a first transmission shaft;

[0011] an accessory having a second transmission shaft, the second transmission shaft being in transmission connection with the first transmission shaft; and

[0012] a sealing assembly having a fitting part, the fitting part being arranged on the inner or outer periphery of the sealing assembly, the sealing assembly being in fitting connection with the first transmission shaft or the second transmission shaft through the fitting part, the sealing assembly being clamped between the first transmission shaft and the second transmission shaft in an assembled state;

[0013] wherein at least a part of the sealing assembly is made of a shape memory alloy, so that the sealing assembly is deformed radially to interference fit with the second transmission shaft in a high-temperature state.

[0014] In one or more embodiments, the first transmission shaft has a shaft hole, a first fitting part is arranged in the shaft hole, an outer periphery of the second transmission shaft is provided with a second fitting part, and the second transmission shaft is inserted into the shaft hole so that the first fitting part is in transmission connection with the second fitting part.

[0015] In one or more embodiments, the fitting part is an external thread arranged on the outer periphery of the sealing assembly, and an internal thread is arranged in the shaft hole, and the sealing assembly is in threaded connection with the first transmission shaft in an assembled state.

[0016] In one or more embodiments, an inner periphery of the sealing assembly is provided with a deformation part made of the shape memory alloy, and the deformation part is configured to be in clearance fit with the second transmission shaft in a normal-temperature state and in interference fit with the second transmission shaft in a high-temperature state.

[0017] In one or more embodiments, one end of the sealing assembly is provided with an operating part.

[0018] In one or more embodiments, the operating part is a hexagonal head.

[0019] In one or more embodiments, the first fitting part and the second fitting part are splines.

[0020] In one or more embodiments, the first fitting part and the second fitting part are gears.

[0021] In one or more embodiments, a sealing ring is further arranged between the first transmission shaft and the second transmission shaft, and the sealing ring is spaced apart from the sealing assembly along the axial direction of the second transmission shaft.

[0022] In one or more embodiments, a lubricating oil cavity is further included, and lubricating oil flows from the lubricating oil cavity to the connection between the first transmission shaft and the second transmission shaft.

[0023] The sealing ring is closer to the lubricating oil cavity than the sealing assembly.

[0024] The beneficial effects of the present application are as follows:

[0025] The sealing assembly of the aero-engine accessory drive system is based on a shape memory alloy aero-engine fireproof sealing structure. Compared with the commonly used shaft hole small gap fit structure, the sealing assembly can automatically adjust between the gap fit and interference fit states according to the use requirements due to the large deformation recovery capability of the shape memory alloy after being heated, thereby eliminating the extremely high requirement for machining precision and facilitating assembly and disassembly. Compared with the idea of developing a super-high-temperature-resistant rubber ring, the shape memory alloy has been applied, and the development cycle is short and the cost is controllable. At the same time, the sealing assembly 3 of the aero-engine accessory drive system can realize good lubricating oil sealing function in the engine fire state, prevent lubricating oil leakage, avoid fire area expansion, and improve reliability and safety. The fireproof sealing structure has good assembly, maintainability, and economy, and has small modification to the existing engine structure, and is suitable for large-scale popularization and use.

[0026] The above description is only a summary of the technical solutions of the present application. In order to enable the technical means of the present application to be more clearly understood, and to be implemented according to the content of the description, and in order to enable the above and other purposes, characteristics and advantages of the present application to be more apparent and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0027] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not meant to limit the present application. Moreover, the same reference numerals in the attached drawings indicate the same or similar elements. In the drawings:

[0028] Figure 1 A schematic view of the application position of the aero-engine accessory drive system in the engine is schematically shown;

[0029] Figure 2 A semi-partial view of the connection between the transmission gear box and the accessory in the aero-engine accessory drive system is shown;

[0030] Figure 3Fig. 2 shows a half cutaway perspective view of the connection between the transmission gear box and the accessories in the aero-engine accessory drive system of the present application;

[0031] Figure 4 Fig. 5 shows a perspective view of an embodiment of the sealing assembly of the present application;

[0032] Figure 5 Fig. 6 shows a half cutaway view of an embodiment of the sealing assembly of the present application;

[0033] Figure 6 Fig. 7 shows a half cutaway view of the transmission connection between the first transmission shaft and the second transmission shaft. DETAILED DESCRIPTION

[0034] The embodiments of the technical solution of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments of the present application, and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0036] In order to solve the problems of the existing aero-engine fireproof sealing device being difficult to implement and poor sealing effect, according to some embodiments of the present application, an aero-engine accessory drive system is provided. In order to facilitate understanding of the relationship between the aero-engine accessory drive system and the whole aero-engine, please refer to Figure 1 , Figure 1 Fig. 1 schematically shows the application position of the aero-engine accessory drive system in the engine. It can be understood that Figure 1 is only a schematic view, and is not drawn according to the real part scale. The aero-engine includes a fan supercharging stage 91, an intermediate casing 92, a high pressure compressor 93, a combustion chamber 94, a high pressure turbine 95, an inter-stage casing 96, a low pressure turbine 97, a transmission gear box 98, and accessories 99. In this paper, the transmission gear box 98 and the accessories 99 together constitute the aero-engine accessory drive system.

[0037] Figure 2 Fig. 2 shows a half cutaway perspective view of the connection between the transmission gear box and the accessories in the aero-engine accessory drive system of the present application, Figure 3A half cutaway perspective view of the connection between a transmission gear box and an accessory in an aero-engine accessory drive system is shown. The transmission gear box 98 has a first transmission shaft 1 and the accessory 99 has a second transmission shaft 2, which is in transmission connection with the first transmission shaft 1 to enable power to be transmitted from the transmission gear box 98 to the accessory 99 within the aero-engine.

[0038] A sealing assembly 3 is also provided between the first transmission shaft 1 and the second transmission shaft 2 at the connection between the transmission gear box 99 and the accessory 99. The sealing assembly 3 has a mating portion 31 provided on the inner or outer periphery of the sealing assembly 3. The sealing assembly 3 is in mating connection with the first transmission shaft 1 or the second transmission shaft 2 through the mating portion 31, so that in the assembled state as shown in the figure, the sealing assembly 3 is clamped between the first transmission shaft 1 and the second transmission shaft 2.

[0039] At least a part of the sealing assembly 3 is made of a shape memory alloy (SMA) to enable the sealing assembly 3 to deform radially in a high temperature state to form an interference fit with the second transmission shaft 2, thereby achieving a sealing structure between the first transmission shaft 1 and the second transmission shaft 2 to seal.

[0040] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0041] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The occurrence of the phrase in various places in the specification is not necessarily all referring to the same embodiment, nor is it necessarily referring to a particular embodiment in isolation or in preference to other embodiments. It is explicitly and implicitly understood by those skilled in the art that embodiments described herein can be combined with other embodiments.

[0042] In some embodiments of the aero-engine accessory drive system, as shown in Figures 2-3 The first transmission shaft 1 has a shaft hole 10 in which a first mating portion 11 is provided, and the second transmission shaft 2 has a second mating portion 21 provided on the outer periphery of the second transmission shaft 2. The second transmission shaft 21 is inserted into the shaft hole 10 so that the first mating portion 11 and the second mating portion 21 are in transmission connection, thereby achieving transmission connection between the transmission gear box 98 and the accessory 99. In other embodiments different from those shown in the figure, the shaft hole can be provided in the second transmission shaft, and the first transmission shaft can be inserted into the second transmission shaft. In this embodiment, the first mating portion is provided on the outer periphery of the first transmission shaft, and the second mating portion is provided on the inner periphery of the second transmission shaft.

[0043] Figure 4 A perspective view of one embodiment of this sealing assembly is shown. Figure 5 A half-sectional schematic diagram of one embodiment of this sealing assembly is shown. Figures 4-5 In the illustrated embodiment, the mating part 31 of the sealing component 3 is an external thread provided on the outer periphery of the sealing component 3, and an internal thread 101 is provided in the shaft hole 10. In the assembled state, the sealing component 3 is threadedly connected to the first drive shaft 1 and simultaneously fitted onto the outer periphery of the second drive shaft 2. In this embodiment, the sealing component 3 and the first drive shaft 1 can be fixedly connected by a threaded connection, which is simple to assemble and has a simple structure. Of course, in other suitable embodiments, the sealing component 3 and the first drive shaft 1 can be fixedly connected by other methods, including but not limited to cylindrical surface interference fit, pin connection, bolt connection, etc.

[0044] Furthermore, such as Figure 5 As shown, a deformation portion 32 is provided on the inner circumference of the sealing component 3. The deformation portion 32 is made of shape memory alloy. The deformation portion 32 is configured such that, at room temperature, the inner circumference of the sealing component 3 is slightly larger than the outer circumference of the second drive shaft 2, allowing for a clearance fit with the second drive shaft 2. At high temperature, the deformation portion 32, made of shape memory alloy, deforms due to heat, causing the inner diameter of the sealing component 3 to shrink until the sealing component 3 and the second drive shaft 2 are interference-fitted, thereby forming a seal between the first drive shaft 1 and the second drive shaft 2. In the embodiment shown in the figure, only a portion of the sealing component 3 is configured with a deformation portion 32 made of shape memory alloy. It is understood that in some other suitable embodiments, depending on the required deformation of the sealing component 3 under fire conditions, the entire sealing component 3 can be configured to be made of shape memory alloy.

[0045] At the same time, Figure 4 In the embodiment shown, the sealing component 3 is threaded to the inner circumference of the first drive shaft 1. In other suitable embodiments, the sealing component 3 can also be fixedly connected to the outer circumference of the second drive shaft 2 by means of other methods including but not limited to threaded connection, cylindrical surface interference fit, pin connection, bolt connection, etc. At room temperature, the sealing component 3 is clearance-fitted with the first drive shaft 1. At high temperature, the sealing component 3 deforms to be interference-fitted with the inner circumference of the first drive shaft 1.

[0046] In some embodiments of the aircraft engine accessory transmission system, one end of the sealing assembly 3 is provided with an operating part 33, through which a tool can apply torque to the sealing assembly 3 so as to tighten the sealing assembly 3 into the first drive shaft 1 or unscrew it from the first drive shaft 1.

[0047] Further, in one specific embodiment, the operation part 3 is a hexagonal head. Of course, in other suitable embodiments, the operation part 3 can also be other configurations that are easy to be clamped to apply torque, such as a square head, a petal type, etc.

[0048] Figure 6 A half-section view of the transmission connection between the first transmission shaft and the second transmission shaft is shown as Figure 6 As shown, the first fitting part 11 and the second fitting part 21 are splines, and the first transmission shaft 1 and the second transmission shaft 2 are transmission connected through the spline structure.

[0049] In some other embodiments different from those shown in the drawings, the first fitting part 11 and the second fitting part 21 can also be gears, and transmission is achieved through gear engagement. In some other embodiments, the first fitting part 11 and the second fitting part 21 can also be interference-fitted cylindrical surfaces.

[0050] In some embodiments of the aero-engine accessory drive system, a sealing ring 4 is further arranged between the first transmission shaft 1 and the second transmission shaft 2, and the sealing ring 4 is arranged spaced apart from the sealing assembly 3 along the axial direction a of the second transmission shaft 2. When there is no fire in the normal temperature environment, the first transmission shaft 1 and the second transmission shaft 2 are sealed through the sealing ring 4.

[0051] In some embodiments of the aero-engine accessory drive system, a lubricating oil cavity 5 is further included, and lubricating oil flows out from the lubricating oil cavity 5 to the connection between the first transmission shaft 1 and the second transmission shaft 2, which can be a spline or a gear structure, for cooling and lubrication. The sealing ring 4 is closer to the lubricating oil cavity 5 than the sealing assembly 3, so that in the normal temperature state, the sealing is achieved by the sealing ring 4, and when a high-temperature working condition such as fire occurs, if the sealing ring 4 fails, the sealing between the first transmission shaft 1 and the second transmission shaft 2 is achieved through the deformation of the sealing assembly 3.

[0052] In assembly, the threaded sealing assembly 3 is first screwed with the internally threaded first transmission shaft 1, then the sealing ring 4 is assembled to the second transmission shaft 2, and then the second transmission shaft 2 is assembled into the hole formed by the externally threaded sealing assembly 3 and the internally threaded first transmission shaft 1 along the axial direction from right to left.

[0053] When the sealing assembly 3 with shape memory alloy does not deform and recover at low temperature, it is still in small gap fit with the second transmission shaft 2; when the fire occurs, the temperature rises to the deformation recovery temperature, the shape memory alloy will deform and recover, the sealing assembly 3 hole diameter decreases, resulting in the second transmission shaft 2 and the sealing assembly 3 become interference fit. But at this time, the torque is still mainly transmitted by the spline or gear, and the interference fit is only used as a lubricating oil sealing function. After the fire is eliminated, the temperature decreases, the sealing assembly 3 hole diameter increases, and the sealing assembly 3 and the second transmission shaft 2 again become small gap fit, so as to facilitate the disassembly of the accessory for inspection and the like.

[0054] The sealing assembly 3 used in the aircraft engine accessory drive system is based on the shape memory alloy aircraft engine fireproof sealing structure. Compared with the currently commonly used shaft hole small gap fit structure, due to the large deformation recovery ability of the shape memory alloy after heating, the sealing assembly 3 can automatically adjust between the gap fit-interference fit two states according to the use requirements, which saves the extremely high requirement for the machining precision, and is easy to assemble and disassemble. Compared with the idea of developing a super high temperature resistant rubber ring, the shape memory alloy has been applied, and the development cycle is short and the cost is controllable. At the same time, the sealing assembly 3 used in the aircraft engine accessory drive system can realize good lubricating oil sealing function under the engine fire state, prevent lubricating oil leakage, avoid fire area expansion, improve reliability and safety. The fireproof sealing structure has good assembly, maintainability and economy, and has small modification amount to the existing engine structure, and is suitable for large-scale popularization and use.

[0055] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0056] It should be understood that the "along" a certain direction mentioned in the text means that there is at least a component in the direction, preferably the included angle with the direction is within 10°, more preferably the included angle is within 5°.

[0057] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced equivalently. Such modifications or replacements do not change the essence of the corresponding technical solutions, which should be covered in the scope of the present application. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An aircraft engine accessory drive system, characterized by, The utility model relates to a transmission gear box, comprising: a first transmission shaft; an accessory having a second transmission shaft, the second transmission shaft being in transmission connection with the first transmission shaft; and a sealing assembly having a matching part arranged on the inner or outer periphery of the sealing assembly, the sealing assembly being in matching connection with the first transmission shaft or the second transmission shaft through the matching part, the sealing assembly being clamped between the first transmission shaft and the second transmission shaft in an assembled state; wherein at least a part of the sealing assembly is made of a shape memory alloy, so that the sealing assembly is deformed radially to interference fit with the second transmission shaft in a high-temperature state; the first transmission shaft has a shaft hole, a first matching part is arranged in the shaft hole, the outer periphery of the second transmission shaft is provided with a second matching part, the second transmission shaft is inserted into the shaft hole, so that the first matching part and the second matching part are in transmission connection; the matching part is an external thread arranged on the outer periphery of the sealing assembly, an internal thread is arranged in the shaft hole, and the sealing assembly is in threaded connection with the first transmission shaft in an assembled state; the inner periphery of the sealing assembly is provided with a deformation part made of the shape memory alloy, and the deformation part is configured to gap fit with the second transmission shaft in a normal-temperature state and interference fit with the second transmission shaft in a high-temperature state.

2. The aeroengine accessory drive system of claim 1, wherein, One end of the sealing assembly is provided with an operating part.

3. The aeroengine accessory drive system of claim 2, wherein, The operating part is a hexagonal head.

4. The aeroengine accessory drive system of claim 1, wherein, The first matching part and the second matching part are splines.

5. The aeroengine accessory drive system of claim 1, wherein, The first matching part and the second matching part are gears.

6. The aeroengine accessory drive system of claim 1, wherein, A sealing ring is further arranged between the first transmission shaft and the second transmission shaft, and the sealing ring is arranged spaced apart from the sealing assembly in the axial direction of the second transmission shaft.

7. The aeroengine accessory drive system of claim 6, wherein, A lubricating oil cavity is further arranged, and lubricating oil flows from the lubricating oil cavity to the connection between the first transmission shaft and the second transmission shaft. The sealing ring is closer to the lubricating oil cavity than the sealing assembly.

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