Gas Turbine Fan Blade Lock Assembly with Interference Pins
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Solution Overview
Problem
Existing gas turbine engine fan blade lock assemblies face challenges in securely retaining fan blades, particularly in preventing both axial and rotational movements, while ensuring efficient assembly and disassembly processes.
Innovation Solution
A fan blade lock assembly featuring a fan hub with circumferentially spaced slots and a lock ring that moves between unlocked and locked positions, utilizing discrete pins in an interference fit to prevent rotational movement, and a nose cone as a retainer to secure the pins in place, facilitating assembly and reassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a lock ring is used to axially retain fan blades, then axial movement is prevented, but rotational movement cannot be prevented without additional components
Solution Approach 1:
The patent combines the axial retention function (lock ring) and rotational locking function (discrete pins) into a single integrated assembly. The lock ring includes both axial retention capability through its engagement with the fan hub slots and rotational locking capability through the discrete pins that prevent rotation while maintaining axial retention. This merging eliminates the need for separate components for each function.
Solution Approach 2:
The lock ring is segmented into multiple discrete pins distributed circumferentially around the lock ring. Each pin independently prevents rotational movement at its location, and collectively they provide comprehensive rotational locking while the lock ring as a whole provides axial retention. This segmentation allows the rotational and axial functions to be achieved through different structural elements within the same component.
2Stability of the object's composition
If discrete pins are used to prevent rotational movement, then rotational stability is improved, but assembly complexity increases
Solution Approach 1:
The discrete pins are pre-positioned in the lock ring during manufacturing, with alignment features (such as slots or recesses) that guide the pins into their correct positions. This preliminary action ensures that during assembly, the pins are already in the correct orientation and position, simplifying the final assembly process and ensuring proper alignment without requiring complex alignment procedures.
Solution Approach 2:
The patent introduces an intermediary element (such as a retaining ring or additional fastening mechanism) that secures the discrete pins to the lock ring. This intermediary component simplifies the assembly process by providing a clear sequence: first assemble the lock ring with pins in place, then secure the pins using the intermediary element. This mediator makes the assembly more straightforward and ensures proper positioning.
3Reliability
If multiple components are used for locking, then retention reliability is improved, but disassembly time increases
Solution Approach 1:
By merging the axial retention and rotational locking functions into a single lock ring assembly with integrated discrete pins, the patent reduces the number of separate components that need to be disassembled. The lock ring can be removed as a single unit from the fan hub, and the discrete pins can be released simultaneously, significantly reducing disassembly time compared to separate axial and rotational locking components.
Solution Approach 2:
The discrete pins are designed with preliminary features such as slots, recesses, or alignment marks that indicate their correct positions and facilitate quick removal. These preliminary design features allow for rapid disassembly by guiding the removal process and ensuring that all pins can be removed efficiently without requiring complex alignment or positioning procedures during disassembly.
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 solution effectively retains fan blades by preventing rotational movement and allows for efficient assembly and disassembly, enhancing the structural integrity and operational reliability of the gas turbine engine fan section.
Implementation Method 1
The pin engages the lock ring and the fan hub in an interference fit
Data Source
AI summary
A gas turbine engine fan blade lock assembly includes a fan hub that has blade slots each configured to receive a root of a fan blade. The fan hub includes circumferentially spaced first slots. A lock ring is configured to move between unlocked and locked positions. The lock ring includes circumferentially spaced second slots aligned with the first slots in the locked position, and multiple discrete pins. Each pin is configured to be slidably received in paired first and second slots in the locked position to prevent rotational movement of the lock ring relative the fan hub.