Aero-engine accessory transmission system

Abstract

The invention aims to provide an aero-engine accessory transmission system. The aero-engine accessory transmission system comprises a transmission gear box, an accessory and a sealing assembly. The transmission gearbox is provided with a first transmission shaft, and the accessory is provided with a second transmission shaft which is in transmission connection with the first transmission shaft. The sealing assembly is provided with a matching part, is in matched connection with the first transmission shaft or the second transmission shaft through the matching part, and is clamped between the first transmission shaft and the second transmission shaft. At least one part of the sealing assembly is made of shape memory alloy, so that the sealing assembly deforms in the radial direction in the high-temperature state till the sealing assembly is in interference fit with the second transmission shaft. By means of the aero-engine accessory transmission system, the fireproof requirement can be met, and meanwhile implementation is easy.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbine engines, and in particular to an aircraft engine accessory transmission system. Background Art

[0002] Gas turbine engines are the most widely used aircraft engines at present and are known as one of the "crown jewels of industry". During operation, aircraft gas turbine engines not only provide power to the aircraft, but are also responsible for outputting power to drive the engine's accessory transmission mechanism, and then drive various electrical equipment carried on the aircraft. Conversely, during the starting phase, the starter in the accessory outputs power to the engine in the opposite direction through the gear shaft of the accessory transmission gearbox, drives the engine, and then drives the aircraft to take off. The accessory transmission mechanism and various accessories use a large number of gear meshing methods to transmit power. The gear meshing points, bearings, splines and other positions all require lubricating oil cooling and lubrication. During the oil supply-return process, care must be taken to prevent oil leakage. Therefore, it is inevitable to use more rubber rings for oil sealing in the accessory transmission system.

[0003] At present, domestic and foreign civil aviation airworthiness regulations have put forward requirements for engine fire protection. As a lubricating oil delivery component, the fire protection level of the accessory transmission mechanism should be fireproof, that is, the component can withstand an average flame temperature of 1100℃ (about 2000℉) for at least 15 minutes when exposed to a hot field or other specific environment, while maintaining the original function or structural integrity. However, the rubber rings commonly used in the accessory transmission mechanism will creep, age, and carbonize under such high temperature conditions, resulting in seal failure and lubricating oil leakage, thereby causing the fire zone to expand. Therefore, in order to meet the fire protection requirements, it is urgent to solve the problem of lubricating oil leakage caused by the aging of rubber rings under ultra-high temperatures.

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

[0005] One is to research new elastic materials to make the sealing ring heat-resistant to flame temperature, so as to ensure the sealing of the sealing ring is reliable under ultra-high temperature. And under normal working conditions, the sealing ring can still achieve the established sealing function.

[0006] Secondly, the seal shaft-hole fit is precisely designed to minimize the shaft-hole clearance as much as possible, so that the oil leakage can still be kept small in the event of rubber ring failure.

[0007] However, the technical route selected in Plan 1 has a long R&D cycle and high R&D cost for new materials, which violates the economic requirements of civil aviation; the technical route selected in Plan 2 has extremely high requirements for processing accuracy and design personnel, which may easily lead to problems such as difficulty in assembling the shaft and hole and friction during operation, and will greatly increase the processing cost. Summary of the invention

[0008] The object of the present invention is to provide an aircraft engine accessory transmission system which can meet the fire protection requirements and is easy to implement.

[0009] An aircraft engine accessory transmission system for achieving the above-mentioned purpose comprises:

[0010] A transmission gearbox having a first transmission shaft;

[0011] An accessory having a second transmission shaft, the second transmission shaft being drivingly connected to the first transmission shaft; and

[0012] A sealing assembly having a matching portion, wherein the matching portion is arranged on the inner periphery or the outer periphery of the sealing assembly, wherein the sealing assembly is matched and connected with the first transmission shaft or the second transmission shaft through the matching portion, and in an assembled state, the sealing assembly is sandwiched between the first transmission shaft and the second transmission shaft;

[0013] Wherein, at least a portion of the sealing component is made of shape memory alloy, so that the sealing component can be radially deformed to an interference fit with the second transmission shaft under high temperature.

[0014] In one or more embodiments, the first transmission shaft has an axial hole, a first matching portion is arranged in the axial hole, a second matching portion is arranged on the outer periphery of the second transmission shaft, and the second transmission shaft is inserted into the axial hole so that the first matching portion is transmission-connected with the second matching portion.

[0015] In one or more embodiments, the mating portion is an external thread disposed on the outer periphery of the sealing assembly, and an internal thread is disposed in the axial hole. In the assembled state, the sealing assembly is threadedly connected to the first transmission shaft.

[0016] In one or more embodiments, a deformation portion is provided on the inner periphery of the sealing assembly, and the deformation portion is made of the shape memory alloy. The deformation portion is configured such that, at normal temperature, the sealing assembly and the second transmission shaft have a clearance fit, and at high temperature, the sealing assembly and the second transmission shaft have an interference fit.

[0017] In one or more embodiments, an operating portion is configured at one end of the sealing assembly.

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

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

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

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

[0022] In one or more embodiments, it further includes a lubricating oil cavity, from which lubricating oil flows out to the connection between the first transmission shaft and the second transmission shaft;

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

[0024] The beneficial effects of the present invention are:

[0025] The sealing component used in the transmission system of the aircraft engine accessories is an aircraft engine fireproof sealing structure based on shape memory alloy. Compared with the currently commonly used shaft hole small clearance matching structure, the sealing component can automatically adjust between the clearance matching and interference matching states according to the use requirements by virtue of the large deformation recovery ability of the shape memory alloy after being heated, eliminating the extremely high requirements for processing accuracy and being easy to assemble and disassemble. Compared with the idea of ​​developing ultra-high temperature resistant rubber rings, shape memory alloys have been applied, with a short research and development cycle and controllable costs. At the same time, the sealing component 3 used in the transmission system of the aircraft engine accessories can achieve a good lubricating oil sealing function when the engine is on fire, prevent lubricating oil leakage, avoid the expansion of the fire zone, and improve reliability and safety. This fireproof sealing structure has good assembly, maintainability, and economy, and the amount of modification to the existing engine structure is small, which is suitable for large-scale promotion and use.

[0026] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0028] Figure 1 The schematic diagram shows the application position of the aircraft engine accessory transmission system in the engine;

[0029] Figure 2 A half-section schematic diagram of the connection between the transmission gearbox and the accessory in the aircraft engine accessory transmission system is shown;

[0030] Figure 3A half-cut perspective view of the connection between the transmission gearbox and the accessory in the aircraft engine accessory transmission system is shown;

[0031] Figure 4 A three-dimensional schematic diagram of an embodiment of the sealing assembly is shown;

[0032] Figure 5 A half-section schematic diagram of an embodiment of the sealing assembly is shown;

[0033] Figure 6 A half-section schematic diagram of the transmission connection between the first transmission shaft and the second transmission shaft is shown. DETAILED DESCRIPTION

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

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0036] In order to solve the problem that the fireproof sealing device in the existing aircraft engine is difficult to realize and the sealing effect is poor, according to some embodiments of the present application, an aircraft engine accessory transmission system is provided. In order to facilitate understanding of the relationship between the aircraft engine accessory transmission system and the aircraft engine as a whole, please refer to Figure 1 , Figure 1 The schematic diagram of the application position of the aircraft engine accessory transmission system in the engine is schematically shown. It can be understood that: Figure 1 It is only a schematic diagram and is not drawn according to the real parts scale. The aircraft engine includes a fan boost stage 91, an intermediate casing 92, a high-pressure compressor 93, a combustion chamber 94, a high-pressure turbine 95, an interstage casing 96, a low-pressure turbine 97, a transmission gearbox 98 and accessories 99. In this article, the transmission gearbox 98 and accessories 99 together constitute the aircraft engine accessory transmission system.

[0037] Figure 2 A half-section schematic diagram of the connection between the transmission gearbox and the accessory in the aircraft engine accessory transmission system is shown. Figure 3A half-cut perspective view of the connection between the transmission gearbox and the accessory in the aircraft engine accessory transmission system is shown. The transmission gearbox 98 has a first transmission shaft 1, and the accessory 99 has a second transmission shaft 2, which is transmission-connected to the first transmission shaft 1 so that power can be transmitted from the transmission gearbox 98 to the accessory 99 in the aircraft 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, and the mating portion 31 is provided on the inner periphery or the outer periphery of the sealing assembly 3. The sealing assembly 3 is matingly connected 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] Among them, at least a part of the sealing component 3 is made of shape memory alloy (SMA), so that the sealing component 3 can be radially deformed to an interference fit with the second transmission shaft 2 under high temperature, thereby forming a sealing structure between the first transmission shaft 1 and the second transmission shaft 2 for sealing.

[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 "multiple" is more than two, unless otherwise clearly and specifically defined.

[0041] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0042] In some embodiments of the aircraft engine accessory transmission system, Figures 2 to 3 As shown, the first transmission shaft 1 has an axial hole 10, a first matching portion 11 is arranged in the axial hole 10, a second matching portion 21 is arranged on the outer periphery of the second transmission shaft 2, and the second transmission shaft 21 is inserted into the axial hole 10 so that the first matching portion 11 is transmission-connected with the second matching portion 21, thereby realizing the transmission connection between the transmission gear box 98 and the accessory 99. In other embodiments different from those shown in the figure, the axial hole can also be arranged in the second transmission shaft, and the first transmission shaft can be penetrated into the second transmission shaft. In this embodiment, the first matching portion is arranged on the outer periphery of the first transmission shaft, and the second matching portion is arranged on the inner periphery of the second transmission shaft.

[0043] Figure 4 A three-dimensional schematic diagram of an embodiment of the sealing assembly is shown. Figure 5 A half-section schematic diagram of an embodiment of the sealing assembly is shown. Figures 4 to 5 In the embodiment shown, the mating portion 31 of the sealing component 3 is an external thread arranged on the outer periphery of the sealing component 3, and the shaft hole 10 is provided with an internal thread 101. In the assembled state, the sealing component 3 is threadedly connected to the first transmission shaft 1 and is sleeved on the outer periphery of the second transmission shaft 2. In this embodiment, the sealing component 3 can be fixedly connected to the first transmission shaft 1 by threaded connection, and the assembly is simple and the structure is simple. Of course, in some other suitable embodiments, the sealing component 3 and the first transmission shaft 1 can be fixedly connected by other means including but not limited to cylindrical interference fit, pin connection, bolt connection, etc.

[0044] Furthermore, if Figure 5 As shown, a deformation part 32 is provided on the inner periphery of the sealing component 3, and the deformation part 32 is made of a shape memory alloy. The deformation part 32 is configured such that, at normal temperature, the inner periphery of the sealing component 3 is slightly larger than the outer periphery of the second transmission shaft 2, so that it is loosely matched with the second transmission shaft 2. Under high temperature conditions, the deformation part 32 made of the shape memory alloy is deformed by heat, so that the inner diameter of the sealing component 3 is reduced until the sealing component 3 and the second transmission shaft 2 are interference-fitted, so as to form a seal between the first transmission shaft 1 and the second transmission shaft 2. In the embodiment shown in the figure, only a part of the sealing component 3 is configured as the deformation part 32 made of a shape memory alloy. It can be understood that in some other suitable embodiments, according to the required deformation size of the sealing component 3 under the fire state, the sealing component 3 can be configured as a whole to be made of a shape memory alloy.

[0045] At the same time, Figure 4 In the embodiment shown in , the sealing assembly 3 is threadedly connected to the inner circumference of the first transmission shaft 1. In some other suitable embodiments, the sealing assembly 3 may also be fixedly connected to the outer circumference of the second transmission shaft 2 by other means including but not limited to threaded connection, cylindrical interference fit, pin connection, bolt connection, etc. At normal temperature, the sealing assembly 3 has a clearance fit with the first transmission shaft 1. At high temperature, the sealing assembly 3 is deformed to have an interference fit with the inner circumference of the first transmission shaft 1.

[0046] In some embodiments of the aircraft engine accessory transmission system, an operating portion 33 is provided at one end of the sealing assembly 3, and a tool can apply torque to the sealing assembly 3 through the operating portion 33 to facilitate tightening the sealing assembly 3 into the first transmission shaft 1, or unscrewing it from the first transmission shaft 1.

[0047] Furthermore, in a specific embodiment, the operating portion 3 is a hexagonal head. Of course, in other suitable embodiments, the operating portion 3 may also be other configurations that are easy to be clamped to apply torque, such as a square head, a petal-shaped head, etc.

[0048] Figure 6 A half-section schematic diagram of the transmission connection between the first transmission shaft and the second transmission shaft is shown. Figure 6 As shown, the first matching portion 11 and the second matching portion 21 are splines, and the first transmission shaft 1 and the second transmission shaft 2 are transmission connected via the spline structure.

[0049] In some other embodiments different from those shown in the figure, the first matching portion 11 and the second matching portion 21 may also be gears, and transmission is achieved through gear meshing. In other embodiments, the first matching portion 11 and the second matching portion 21 may also be cylindrical surfaces with interference fit.

[0050] In some embodiments of the aircraft engine accessory transmission system, a sealing ring 4 is further provided between the first transmission shaft 1 and the second transmission shaft 2. Along the axial direction a of the second transmission shaft 2, the sealing ring 4 and the sealing assembly 3 are arranged at intervals. In a normal temperature environment without a fire, the first transmission shaft 1 and the second transmission shaft 2 are sealed by the sealing ring 4.

[0051] In some embodiments of the aircraft engine accessory transmission system, a lubricating oil cavity 5 is also included, and the 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, and can be used for cooling and lubricating structures such as splines or gears. Among them, the sealing ring 4 is closer to the lubricating oil cavity 5 than the sealing component 3, so that the sealing is achieved by the sealing ring 4 at normal temperature. When a high temperature condition such as a fire occurs, if the sealing ring 4 fails, the sealing is achieved by the deformation generated between the first transmission shaft 1 and the second transmission shaft 2 by the sealing component 3.

[0052] During assembly, firstly, the threaded sealing component 3 is threadedly connected to the first transmission shaft 1 with internal threads, then the sealing ring 4 is assembled to the second transmission shaft 2, and then the second transmission shaft 2 is axially inserted from right to left into the hole formed by the externally threaded sealing component 3 and the first transmission shaft 1 with internal threads.

[0053] When the sealing component 3 with shape memory alloy does not deform and recover at low temperature, it still has a small gap fit with the second transmission shaft 2; when a fire occurs, the temperature rises to the deformation recovery temperature, the shape memory alloy will deform and recover, and the aperture of the sealing component 3 will decrease, resulting in an interference fit between the second transmission shaft 2 and the sealing component 3. However, at this time, the transmission of torque still mainly relies on splines or gears, and the interference fit is only used as a lubricating oil seal. After the fire is extinguished, the temperature drops, the aperture of the sealing component 3 increases, and the sealing component 3 and the second transmission shaft 2 become a small gap fit again, so that the accessories can be disassembled for inspection, etc.

[0054] The sealing component 3 used in the transmission system of the aircraft engine accessories is an aircraft engine fireproof sealing structure based on shape memory alloy. Compared with the currently commonly used shaft hole small clearance matching structure, the sealing component 3 can automatically adjust between the two states of clearance matching and interference matching according to the use requirements by virtue of the large deformation recovery ability of the shape memory alloy after being heated, eliminating the extremely high requirements for processing accuracy and being easy to assemble and disassemble. Compared with the idea of ​​developing ultra-high temperature resistant rubber rings, shape memory alloys have been used, with a short research and development cycle and controllable costs. At the same time, the sealing component 3 used in the transmission system of the aircraft engine accessories can achieve a good lubricating oil sealing function when the engine is on fire, prevent lubricating oil leakage, avoid the expansion of the fire zone, and improve reliability and safety. This fireproof sealing structure has good assembly, maintainability, and economy, and the amount of modification to the existing engine structure is small, which is suitable for large-scale promotion and use.

[0055] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings 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 "along" a certain direction mentioned in the text means that there is at least a component in the direction, preferably, the angle with the direction is within 10°, and more preferably, the angle is within 5°.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. An aircraft engine accessory transmission system, characterized in that: include: A transmission gearbox having a first transmission shaft; An accessory having a second transmission shaft, wherein the second transmission shaft is drivingly connected to the first transmission shaft; as well as A sealing assembly having a matching portion, wherein the matching portion is arranged on the inner periphery or the outer periphery of the sealing assembly, wherein the sealing assembly is matched and connected with the first transmission shaft or the second transmission shaft through the matching portion, and in an assembled state, the sealing assembly is sandwiched between the first transmission shaft and the second transmission shaft; Wherein, at least a portion of the sealing component is made of shape memory alloy, so that the sealing component can be radially deformed to an interference fit with the second transmission shaft under high temperature.

2. The aircraft engine accessory transmission system according to claim 1, characterized in that: The first transmission shaft has an axial hole, a first matching portion is arranged in the axial hole, a second matching portion is arranged on the outer periphery of the second transmission shaft, and the second transmission shaft is inserted into the axial hole so that the first matching portion is connected with the second matching portion in transmission.

3. The aircraft engine accessory transmission system according to claim 2, characterized in that: The matching portion is an external thread arranged on the outer periphery of the sealing component, and an internal thread is arranged in the shaft hole. In the assembled state, the sealing component is threadedly connected to the first transmission shaft.

4. The aircraft engine accessory transmission system according to claim 3, characterized in that: A deformation part is provided on the inner periphery of the sealing component, and the deformation part is made of the shape memory alloy. The deformation part is configured so that, at normal temperature, the sealing component and the second transmission shaft have a clearance fit, and at high temperature, the sealing component and the second transmission shaft have an interference fit.

5. The aircraft engine accessory transmission system according to claim 3, characterized in that: An operating portion is disposed at one end of the sealing component.

6. The aircraft engine accessory transmission system according to claim 5, characterized in that: The operating part is a hexagonal head.

7. The aircraft engine accessory transmission system according to claim 2, characterized in that: The first matching portion and the second matching portion are splines.

8. The aircraft engine accessory transmission system according to claim 2, characterized in that: The first matching portion and the second matching portion are gears.

9. The aircraft engine accessory transmission system according to claim 1, characterized in that: A sealing ring is further provided between the first transmission shaft and the second transmission shaft, and along the axial direction of the second transmission shaft, the sealing ring and the sealing assembly are arranged at intervals.

10. The aircraft engine accessory transmission system according to claim 9, characterized in that: It also includes a lubricating oil cavity, from which lubricating oil flows out to the connection between the first transmission shaft and the second transmission shaft; Wherein, the sealing ring is closer to the lubricating oil cavity than the sealing assembly.

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