Conical Service Tube Locking for Vibration-Resistant Engine Threads
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Solution Overview
Problem
Threaded connections in turbine engines are prone to loosening due to vibrations, impacts, and thermal loads, leading to potential oil leakage and structural instability.
Innovation Solution
A service tube assembly with a locking member featuring a conical surface that frictionally locks against a conical seat on the service tube and bearing housing, secured by a bolt, preventing rotation and enhancing the threaded connection's stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If threaded connections are used to connect service tubes to engine components, then assembly is simplified and installation is easy, but the connection is prone to loosening due to vibrations, impacts, and thermal loads
Solution Approach 1:
The locking member is pre-installed on the service tube before assembly, with its locking surface positioned to engage with the bearing housing. This preliminary preparation ensures that when the service tube is threaded into place, the locking mechanism is already in position to prevent loosening, resolving the contradiction between easy assembly and connection stability.
Solution Approach 2:
A locking member is introduced as an intermediary element between the service tube and the bearing housing. This locking member features a locking surface that engages with a corresponding surface on the bearing housing, creating a mechanical interlock that prevents the service tube from loosening due to vibrations and thermal loads, while maintaining the simplicity of the threaded connection.
2Reliability
If a locking mechanism is added to prevent loosening, then connection stability is improved, but device complexity increases
Solution Approach 1:
The locking member is merged with the service tube assembly, where the locking surface is integrated into the bearing housing structure. This integration reduces the need for separate locking components and simplifies the overall structure, achieving connection stability without significantly increasing device complexity.
Solution Approach 2:
The locking surface and the corresponding surface on the bearing housing are designed with conical geometries. This curved surface design provides effective mechanical interlocking to prevent loosening, while the conical shape allows for self-centering and easy engagement, maintaining structural simplicity.
3Reliability
If the locking surface area is increased to improve locking effectiveness, then connection stability is enhanced, but manufacturing complexity and cost increase
Solution Approach 1:
The locking surfaces are designed with conical geometries rather than large flat surfaces. This curved surface design provides effective mechanical interlocking and locking effectiveness while requiring minimal material and simpler manufacturing processes, avoiding the complexity associated with large-area precision surfaces.
Solution Approach 2:
The conical angle and dimensions of the locking surfaces are optimized to achieve the required locking effectiveness with minimal surface area. By adjusting the geometric parameters of the conical surfaces, the design achieves reliable locking without the need for large, complex manufacturing features.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The conical locking mechanism effectively prevents loosening of the threaded connection, ensuring secure fluid transfer and reducing the risk of leakage while simplifying assembly and potentially lowering engine weight and cost.
Implementation Method 1
a conical surface of the locking member frictionally engaging with a conical seat
Data Source
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AI summary
A service tube assembly (22) comprising a service tube (26) having a threaded end portion (26a) and a shoulder (26b). The outer shoulder (26b) has a conical surface (26c) converging in a direction away from the threaded end portion (26a). The threaded end portion (26a) is threadably engaged with a mating part (28). The mating part (28) has a seat surface (33) which cooperates with the shoulder (26b) of the service tube (26) to form a conical seat. The assembly further includes a locking member (32) having an outer conical surface (32a) complementary to the conical seat. A mechanical fastener (34) is provided for releasably holding the locking member (32) against the conical seat.