Gas Turbine Shaft Plug With Wedge-Actuated Sealing Legs
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Solution Overview
Problem
Existing plug designs for gas turbine engine shafts fail to effectively seal and secure the plug within the shaft under oil pressure and temperature conditions, as they are not adequately designed to withstand these factors.
Innovation Solution
A plug device with a sealing body and radially projecting legs that can move between contracted and deployed positions, secured by a wedge mechanism, which engages with shaft projections to ensure a tight seal and secure fit within the shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plug is designed to seal the shaft bore, then sealing effectiveness is improved, but the plug must withstand high oil pressure and temperature which increases design complexity and material requirements
Solution Approach 1:
The plug incorporates movable legs that can transition between retracted and engaged positions. During installation, legs are retracted to allow insertion into the shaft bore. Once positioned, the legs are forced outward by oil pressure or a wedging mechanism to engage with shaft projections, creating a secure seal that adapts to the shaft's internal geometry.
Solution Approach 2:
The plug is divided into distinct functional components: a sealing body for blocking the bore, multiple legs for engaging shaft projections, and a wedging mechanism for actuating the legs. This segmentation allows each component to be optimized independently for its specific function while simplifying the overall design and assembly process.
2Reliability
If the plug legs are made displaceable to engage shaft projections, then secure fit is improved, but the mechanism to displace legs increases device complexity
Solution Approach 1:
The plug design allows oil pressure within the shaft to automatically force the legs outward against the shaft projections, eliminating the need for an external actuation mechanism. The legs are spring-loaded or pre-biased to engage automatically when oil pressure exceeds a certain threshold, providing a self-securing feature that reduces mechanical complexity.
Solution Approach 2:
A wedging mechanism serves as an intermediary between the installation tool and the legs. During installation, a wedge is driven into the plug body, which in turn forces all legs outward simultaneously to engage the shaft projections. This intermediary mechanism provides controlled, uniform actuation of multiple legs without requiring complex individual actuators for each leg.
3Reliability
If the plug is designed to withstand high oil pressure and temperature, then reliability under operating conditions is improved, but material selection and manufacturing difficulty increase
Solution Approach 1:
The plug incorporates a sealing body made from high-temperature, pressure-resistant materials such as hardened steel or nickel-based superalloys. The legs may be made from flexible yet durable materials that can withstand repeated engagement cycles while resisting oil degradation. This composite material approach allows each component to be optimized for its specific mechanical and thermal requirements.
Solution Approach 2:
Different regions of the plug are designed with locally optimized properties: the sealing body features a hardened surface for wear resistance and pressure containment, while the legs incorporate flexible sections for engagement and rigid sections for structural support. The wedging mechanism uses locally strengthened zones to distribute forces evenly during actuation, reducing stress concentrations and improving manufacturability.
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 plug device effectively seals and secures the shaft by expanding its diameter to engage with internal projections, maintaining a tight seal and withstanding the high pressures and temperatures of a gas turbine engine environment.
Implementation Method 1
a wedge operatively engaged to the plug for movement of the wedge relative to the plug, the wedge comprising a portion in operative contact with the legs of the plug unit to displace the legs between said positions as a response to said movement of the wedge
Implementation Method 2
a plug comprising a sealing body shaped to be sealingly received in a bore of the shaft
Data Source
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AI summary
A device for plugging an axially-aligned bore in a shaft (23) of a gas turbine engine comprises a plug (24). A sealing body (40) of the plug (24) is shaped to be sealingly received in a bore (32) of the shaft (23). Legs (50) project from the sealing body (40) and are displaceable between a normally contracted position in which the legs (50) are radially inward relative to a periphery of the bore (32), and a deployed position in which the legs (50) project radially outward and are adapted to engage with shaft projections (33) within the bore (32) of the shaft (23). A wedge (26) is operatively engaged to the plug (24) for movement of the wedge (26) relative to the plug (24). The wedge (26) comprises a portion in operative contact with the legs (50) of the plug unit (24) to displace the legs (50) between said positions as a response to said movement of the wedge (26). A gas turbine engine and a method for plugging a shaft (23) are also provided.