An aircraft engine based compression nut

Abstract

The utility model discloses a kind of compression nuts based on aero-engine, belong to compression nut technical field, including nut body, the bottom of the nut body is integrally formed with transition section, the bottom of the transition section is integrally formed with abutment section, the inner ring of the nut body, the transition section and the abutment section is equipped with thread section, annular groove is provided in the inner ring edge of the nut body top, locking ring is installed in the annular groove.The utility model provides a kind of compression nut, can simultaneously solve the problem of anti-loosening under extreme vibration, anti-creep under superhigh temperature and anti-bite problem in repeated disassembly and assembly.

Description

Technical Field

[0001] This utility model relates to the field of clamping nut technology, and in particular to a clamping nut based on an aero-engine. Background Technology

[0002] Aero engines are a typical complex thermodynamic machine with high temperature, high pressure, and high speed. Their working environment is extremely harsh. The fasteners inside the engine, especially the clamping nuts that connect key hot-end components, must withstand strong broadband vibrations and huge aerodynamic loads at the same time, and maintain long-term reliable operation under extreme high temperature conditions.

[0003] Currently, high-temperature fasteners commonly used in aero engines face multiple challenges in practical applications. First, the strong vibration environment of aero engines, especially high-frequency and high-amplitude vibrations, can easily lead to the attenuation of the preload of the threaded pair and relative rotation, which in turn can cause loosening. If the nuts in critical parts become loose, it may lead to component failure or even catastrophic in-flight engine shutdown accidents.

[0004] Secondly, under high-temperature conditions, the mechanical properties of traditional metal materials decrease significantly and exhibit obvious high-temperature creep. Creep can cause plastic deformation of screws and nuts, resulting in a gradual decrease in the preload of threaded connections over time, which seriously threatens the reliability of the connections.

[0005] Furthermore, to prevent threaded pairs from sticking and seizing under high-temperature conditions, existing technologies typically apply a silver plating coating to the thread surface. However, silver plating coatings have the following drawbacks: when the temperature exceeds a certain level, the silver layer may melt, run off, or react chemically with the substrate and fail. At the same time, the silver coating is relatively soft and is easily scratched and worn during frequent engine maintenance and disassembly, leading to a rapid decline in anti-seizing ability. Once the coating fails, thread seizing can easily occur between the nut and the screw in the nickel-based high-temperature alloy, making it impossible to disassemble the nut normally. Maintenance may require destructive cutting to remove the bolt, resulting in high maintenance costs and long downtime losses. Utility Model Content

[0006] The purpose of this utility model is to provide a compression nut that can simultaneously solve the problems of preventing loosening under extreme vibration, resisting creep under ultra-high temperature, and preventing seizing during repeated disassembly and assembly.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a clamping nut based on an aero-engine, comprising a nut body, a transition section integrally formed at the bottom of the nut body, an abutment section integrally formed at the bottom of the transition section, threaded sections on the inner rings of the nut body, the transition section, and the abutment section, and an annular groove provided on the edge of the inner ring at the top of the nut body, wherein a locking ring is installed in the annular groove.

[0008] As a further description of the above technical solution: the outer ring of the transition section is provided with several convex teeth.

[0009] As a further description of the above technical solution: the inner diameter of the locking ring in the free state is configured to be smaller than the thread diameter of the screw used for mating.

[0010] As a further description of the above technical solution: when the screw is screwed into the threaded section and contacts the locking ring, the locking ring is forced to expand elastically and generate a radial clamping force on the threaded side of the screw.

[0011] As a further description of the above technical solution: the nut body, transition section and abutment section are made of high temperature alloy.

[0012] As a further description of the above technical solution: the nut body, transition section and abutment section are made of ceramic matrix composite material.

[0013] As a further description of the above technical solution: the surface of the threaded section is coated with a high-temperature resistant seizing coating, which is a composite ceramic coating or a diamond-like coating.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are: By applying a new composite coating, the high-temperature seizing resistance, wear resistance, and repeated disassembly and assembly performance of the nut assembly are significantly improved, effectively ensuring the reliability of the aircraft engine maintenance process and the safety of long-term operation. The top of the nut body is designed with an annular groove and a locking ring to form a highly efficient self-locking structure. When the screw is screwed in, the thread will force the locking ring with a smaller inner diameter to expand elastically, thereby generating a strong radial clamping force on the thread side of the screw. Attached Figure Description

[0015] Figure 1 A front view of the present invention is shown; Figure 2 A cross-sectional view of the present invention is shown; Figure 3 This utility model is shown Figure 2 Enlarged view of point A in the middle; Figure 4 A perspective view of the nut assembly of this utility model is shown.

[0016] Legend: 10. Screw; 20. Nut body; 201. Annular groove; 21. Transition section; 22. Abutment section; 23. Threaded section; 24. Raised tooth; 25. Locking ring. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0018] Please see Figures 1-4 This utility model provides a technical solution: a clamping nut based on an aero-engine, suitable for reliable connection and locking in high temperature and high vibration environments.

[0019] like Figure 1 As shown, the fastening system of this embodiment includes a screw 10, which passes through multiple connected parts during use, and its outer threaded portion is fitted with a nut assembly.

[0020] like Figure 2 As shown, the nut assembly is an integral structure, consisting of a nut body 20, a transition section 21, and an abutment section 22. Specifically, the bottom of the nut body 20 is integrally formed with the transition section 21, and the bottom of the transition section 21 is further integrally formed with the abutment section 22.

[0021] In a typical installation state, the bottom surface of the abutment section 22 serves as the bearing surface, directly contacting the surface of the connected parts. The preload is applied by tightening the screw 10 and the nut assembly together. Along the central axis of the nut assembly, the inner rings of the nut body 20, the transition section 21, and the abutment section 22 are all provided with threaded sections 23. The thread specifications of the threaded sections 23 are consistent with the threads of the screw 10, thereby ensuring that the nut assembly can be reliably screwed into the screw 10.

[0022] To meet special installation or anti-rotation requirements, a number of protruding teeth 24 are provided on the outer ring of the transition section 21. These protruding teeth 24 can serve as auxiliary torque input points under specific working conditions. The key innovation of this embodiment is the design of a self-locking structure, which is specifically designed to combat the severe vibration and thermal cycling during the operation of the aero-engine.

[0023] Specifically, the top inner ring edge of the nut body 20 is machined with a precision annular groove 201, in which an independent locking ring 25 is embedded. The inner diameter of the locking ring 25 is designed to be slightly smaller than the major or minor diameter of the screw 10 in the free state, so as to ensure that it can achieve a reliable self-locking effect after installation.

[0024] Working principle: When installing the nut assembly, first screw the screw 10 into the threaded section 23 of the abutment section 22 and the transition section 21. During this stage, the screwing torque is kept normal. When the end of the screw 10 is screwed in further until its thread contacts the locking ring 25 at the top of the nut body 20, the thread crest or flank of the screw 10 will forcefully squeeze the locking ring 25 because the inner diameter of the locking ring 25 is smaller than that of the screw 10.

[0025] The locking ring 25 is rigidly confined within the annular groove 201. The compression of the screw 10 causes the locking ring 25 to undergo elastic deformation and expand outward. This expansion tendency generates a strong radial clamping force acting on the screw 10. This radial clamping force causes the inner surface of the locking ring 25 to firmly engage with the threaded side of the screw 10, thereby generating a large radial frictional force on the threaded side. This frictional force is independent of the direction of vibration.

[0026] Since the anti-loosening friction torque generated by the radial friction force is much greater than the friction torque generated on the thread surface by the axial preload alone, even under the conditions of strong vibration, high G value and severe thermal cycling of the aero-engine, the system can still effectively prevent the relative rotation between the screw 10 and the nut assembly, thereby achieving a highly reliable anti-loosening locking effect.

[0027] In a preferred embodiment, the nut assembly material is a nickel-based superalloy, such as GH416 or Waspaloy, which can maintain excellent yield strength, endurance strength and creep resistance at 650°C to 750°C.

[0028] For implementations with higher requirements, powder metallurgy high-temperature alloys can be selected. Alloys produced by powder metallurgy have a uniform microstructure and low compositional segregation, thereby providing excellent comprehensive mechanical properties and fatigue resistance.

[0029] To meet the higher operating temperature requirements of next-generation aero engines, nut assemblies can be made of high-performance high-temperature alloys, such as nickel-based or cobalt-based alloys. Alternative materials include powder metallurgy high-temperature alloys or directionally solidified / single-crystal alloys, which can exhibit more reliable performance under extreme conditions such as turbine outlet temperatures.

[0030] The nut assembly can be made of ceramic matrix composite material for the manufacture of the nut body 20. In high-temperature environments, especially when undergoing frequent disassembly and maintenance, the threaded parts of the aero-engine fasteners are prone to "seizing" or "cold welding", which can cause the fasteners to jam and become unable to be disassembled.

[0031] Traditional solutions such as silver plating, while providing good solid lubrication at medium and low temperatures, fail in extreme high-temperature environments exceeding 700°C due to silver melting and loss or reaction with the substrate. In addition, the silver layer is easily worn during repeated disassembly and assembly, significantly reducing its anti-seize effect.

[0032] The nut assembly, particularly the surface treatment of the threaded section 23, has been optimized. In a preferred embodiment, a composite ceramic coating is introduced to replace the traditional silver plating coating, and functional enhancement is achieved through a multi-layer or composite structure, such as titanium aluminum nitride + solid lubricant, such as MoS2, WS2 or h-BN.

[0033] Among them, the ceramic coating provides high surface hardness and excellent resistance to high temperature oxidation, effectively protecting the substrate from wear; the solid lubricant provides an extremely low coefficient of friction under high temperature and high pressure conditions, effectively preventing microscopic adhesion of the threaded pair.

[0034] In another embodiment, a diamond-like coating can be selected, whose low coefficient of friction and high hardness are particularly suitable for frequent vibration and anti-galling requirements in medium-temperature environments.

[0035] By applying a new composite coating, the high-temperature seizing resistance, wear resistance, and repeated disassembly and assembly performance of the nut assembly are significantly improved, effectively ensuring the reliability of the aircraft engine maintenance process and the safety of long-term operation. The top of the nut body 20 is designed with an annular groove 201 and a locking ring 25 to form a highly efficient self-locking structure. When the screw 10 is screwed in, the thread will force the locking ring 25 with a smaller inner diameter to expand elastically, thereby generating a strong radial clamping force on the thread side of the screw 10.

[0036] The nut assembly is made of high-performance high-temperature alloys such as GH416Waspaloy, high-grade powder metallurgy alloys, or even ceramic matrix composites. These materials can maintain excellent mechanical strength, endurance strength and creep resistance under extreme high-temperature environments, ensuring that the nut does not experience preload decay due to high-temperature creep during long-term service at the hot end of the engine, thereby ensuring the long-term stability of the connection.

[0037] To address the issue of traditional silver-plated coatings failing under repeated disassembly and assembly and extremely high-temperature environments, composite ceramic coatings or diamond-like coatings are used to replace traditional coatings. These new coatings have extremely high surface hardness, high-temperature stability, and a low coefficient of friction. Even under extreme high-temperature conditions, they can effectively prevent microscopic adhesion and seizing between the metal parts of the threaded pair. In addition, the coating has high hardness and excellent wear resistance, and is not prone to wear and failure during repeated disassembly and assembly. This significantly improves the reusability of the nut, significantly improves the maintainability of the engine, and avoids destructive disassembly caused by thread seizing.

[0038] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A clamping nut based on an aircraft engine, characterized in that, The nut body (20) has a transition section (21) integrally formed at the bottom, and an abutment section (22) integrally formed at the bottom of the transition section (21). The inner rings of the nut body (20), the transition section (21) and the abutment section (22) are all provided with threaded sections (23). The inner ring edge of the top of the nut body (20) is provided with an annular groove (201), and a locking ring (25) is installed in the annular groove (201).

2. The clamping nut based on an aero-engine according to claim 1, characterized in that, The outer ring of the transition section (21) is provided with several protruding teeth (24).

3. A clamping nut based on an aero-engine according to claim 1, characterized in that, The inner diameter of the locking ring (25) in its free state is configured to be smaller than the thread diameter of the screw (10) used for mating.

4. A clamping nut based on an aero-engine according to claim 3, characterized in that, When the screw (10) is screwed into the threaded section (23) and contacts the locking ring (25), the locking ring (25) is forced to expand elastically and generate a radial clamping force on the threaded side of the screw (10).

5. A clamping nut based on an aero-engine according to claim 1, characterized in that, The nut body (20), transition section (21) and abutment section (22) are made of high-temperature alloy.

6. A clamping nut based on an aero-engine according to claim 1, characterized in that, The nut body (20), transition section (21) and abutment section (22) are made of ceramic matrix composite material.

7. A clamping nut based on an aero-engine according to claim 1, characterized in that, The surface of the threaded section (23) is coated with a high-temperature resistant bonding coating, which is a composite ceramic coating or a diamond-like coating.

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