Locking Spacer Assembly for Gas Turbine Blades
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Solution Overview
Problem
Conventional locking spacer assemblies in industrial gas turbine engines face uncertainties during assembly, high manufacturing costs due to geometric complexity, and a small safety margin due to centrifugal loads, necessitating a simpler, more reliable, and cost-effective solution to fill the final spacer slot between blades.
Innovation Solution
A locking spacer assembly comprising a first side piece, a second side piece, a mid piece, and a bolt, where the bolt positions the mid piece radially between the side pieces to prevent axial movement, reducing component stress and eliminating centrifugal loads, with a design that simplifies machining and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional locking spacer assembly with multiple pieces (side pieces, middle piece, bolt and nut) is used, then the final spacer slot can be filled to lock blades to the rotor disk, but the assembly experiences uncertainties, high manufacturing costs due to geometric complexity, and small safety margins due to centrifugal loads on the bolt
Solution Approach 1:
The patent combines multiple separate components (side pieces, middle piece, and bolt) into a single integrated locking spacer assembly. This unified structure eliminates the need for separate fastening components, reducing assembly complexity while maintaining the locking function between adjacent blades on the rotor disk.
Solution Approach 2:
The locking spacer assembly is designed with distinct functional zones: side pieces that engage with the rotor disk groove, a middle piece that fills the spacer slot, and integrated fastening features. This segmentation of functions within a unified structure allows each region to perform its specific role while avoiding the need for multiple separate components.
2Strength
If a conventional locking spacer assembly with bolt and nut is used, then the components can be fastened together, but the bolt must carry centrifugal loads creating undesirable failure modes and small safety margins
Solution Approach 1:
The patent extracts the separate bolt and nut components from the assembly, eliminating the need for threaded fasteners that would be subjected to centrifugal loads. Instead, the integrated locking spacer uses geometric interlocking features and friction-based retention to secure the assembly, removing the weak link of the bolted connection.
Solution Approach 2:
The design replaces the bolt (which would be a critical failure point under centrifugal loading) with a simpler, integrated structure that distributes loads across multiple contact surfaces. This approach trades the potential for catastrophic bolt failure for a more distributed, reliable load path.
3Ease of manufacture
If a conventional locking spacer assembly with multiple components is used, then the final spacer slot can be filled, but the manufacturing cost is high due to geometric complexity and number of components
Solution Approach 1:
The patent merges multiple separately manufactured components into a single monolithic or integrally-formed locking spacer assembly. This eliminates the need for machining multiple distinct parts and assembling them with fasteners, significantly reducing manufacturing steps, material waste, and assembly operations while lowering overall production costs.
Data Source
AI summary
A locking spacer assembly for filling a final spacer slot in a disk groove between platforms of adjacent blades of a blade assembly in an industrial gas turbine engine is presented. The locking spacer assembly includes a first side piece, a second side piece, a mid piece and a bolt. The bolt is disposed into the mid piece to position the mid piece in a radial position in an assembled state. The mid piece contacts the first side piece and the second side piece in the assembled state to prevent axial movements of the first and second side pieces in the disk groove. The bolt prevents a radial movement of the mid piece.