Gas Turbine Bearing Support Structure for Load Path Relocation
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Solution Overview
Problem
Conventional support structures in gas turbine engines face challenges with large radial loads during fan blade-off scenarios, leading to potential slippage and failure in bolted joints, which are exacerbated by the need to manage torque reaction loads, resulting in heavy and large designs that contradict weight reduction and fuel efficiency goals.
Innovation Solution
A support structure configuration that relocates the joint from the fan load path to the compressor load path, using a bolted interface behind the engine section stator, reducing the load on the joint and eliminating it from the torque reaction path, thereby allowing for a smaller and lighter design while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bolted joint is designed to withstand fan blade-off loads, then the joint reliability is improved, but the joint size and weight increase significantly
Solution Approach 1:
The patent extracts the bolted joint from the fan load path by relocating it to the compressor load path. The joint is positioned behind the engine section stator, where it only needs to handle compressor loads rather than the much larger fan loads. This extraction allows the joint to be significantly smaller and lighter while maintaining adequate reliability for its reduced load requirements.
Solution Approach 2:
The patent introduces the engine section stator as an intermediary structure that bears the fan loads. By placing the stator in the fan load path and the bolted joint in the compressor load path, the stator acts as a mediator that protects the joint from direct exposure to high fan loads, allowing the joint to be designed for lower loads only.
2Strength
If the joint is positioned in the fan load path to manage torque reaction loads, then the structural integrity is improved, but the device complexity and size increase
Solution Approach 1:
The patent extracts the joint from the torque reaction path by positioning it behind the engine section stator. The torque reaction loads are managed by the stator and gearbox structure, while the joint only needs to handle compressor loads. This extraction simplifies the overall device design by reducing the structural requirements of the joint and its supporting structures.
Solution Approach 2:
The patent segments the load paths into distinct zones: the fan load path is handled by the stator, while the compressor load path is handled by the joint. This segmentation allows each component to be optimized for its specific load requirements, reducing overall device complexity compared to a unified structure that would need to handle all loads.
3Ease of repair
If a releasable connection is used at the forward end of the support structure, then the ease of maintenance is improved, but the joint size and weight increase to accommodate large radial loads
Solution Approach 1:
The patent extracts the releasable connection from the high-load fan bearing area and relocates it to the lower-load compressor bearing area behind the stator. This relocation allows the connection to be smaller and lighter while still providing the necessary ease of maintenance access to internal engine components.
Solution Approach 2:
The patent changes the radial position dimension of the releasable connection from the forward end (high radial load zone) to a position behind the stator (lower radial load zone). This dimensional relocation allows the connection to be designed for lower loads, reducing its weight while maintaining maintenance accessibility.
Data Source
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AI summary
A bearing support structure (42) for a gas turbine engine (10) located within an internal portion of the engine. The bearing support structure has a plurality of stators (24), a first section (48), a second section (60), a first bearing assembly (58) and a second bearing assembly (86). The first section (48) depends forwardly from the plurality of stators relative to the longitudinal axis. The section second (60) depends rearwardly from the plurality of stators relative to the longitudinal axis and is detachably mounted to the plurality of stators. The first bearing assembly (58) is supported relative to the plurality of stators (24) by the first section (48). The second bearing assembly (86) is supported relative to the plurality of stators (24) by the second section (60). The second section is detachably mounted to the plurality of stators.