Rotor Locking Blade Segmented Bucket Assembly
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Solution Overview
Problem
Existing rotor blade and bucket designs face challenges in retaining blades during assembly, which can reduce load-bearing capacity and affect natural frequencies and balancing of the rotor.
Innovation Solution
A locking blade design featuring a bucket dovetail with a tongue and segmented bucket portions, allowing for secure fastening through strategically placed through holes to prevent radial movement and enhance retention within a rotor groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the assembly gate is cut through wheel hooks in the groove to enable insertion of the blade, then the blade can be assembled into the rotor, but the load bearing capacity of the gate area is reduced
Solution Approach 1:
The bucket is divided into multiple segments (first bucket segment, second bucket segment, third bucket segment) that can be assembled separately around the tongue. This segmentation allows the assembly gate to be formed without compromising the overall structural integrity, as the segments can be joined using fasteners that restore the load-bearing capacity while enabling blade insertion.
Solution Approach 2:
The tongue is designed with a protrusion that extends into the assembly gate before the bucket segments are fully assembled. This preliminary positioning action ensures that the tongue is correctly located and retained by the bucket segments, allowing for proper alignment and secure fastening that maintains load-bearing capacity during the assembly process.
2Ease of operation
If the assembly gate is cut through wheel hooks in the groove to enable insertion of the blade, then the blade can be assembled into the rotor, but the natural frequencies and balancing of the rotor are affected
Solution Approach 1:
The segmented bucket design allows the assembly gate to be formed without creating large continuous openings in the wheel hooks. The segments can be joined with fasteners that minimize disruption to the rotor's mass distribution and structural continuity, thereby reducing the impact on natural frequencies and balancing characteristics.
Solution Approach 2:
The assembly gate is localized to specific regions of the bucket segments rather than being a continuous cut through the entire wheel hook structure. This localized approach minimizes the overall impact on the rotor's structural integrity and mass distribution, preserving natural frequencies and balancing while still enabling blade insertion.
3Reliability
If a locking blade design with tongue and segmented bucket portions is used, then the blade retention is enhanced, but the device complexity increases
Solution Approach 1:
The tongue and bucket segments are designed to integrate seamlessly, with the tongue protrusion fitting into the assembly gate and the bucket segments joining around it. The fasteners serve dual purposes: securing the bucket segments to each other and retaining the tongue in position. This merging of functions reduces the number of separate components needed, thereby reducing complexity while maintaining enhanced blade retention.
Solution Approach 2:
The tongue protrusion automatically positions itself within the assembly gate during assembly, and the bucket segments self-align around the tongue. The fasteners, once inserted, simultaneously secure multiple components (bucket segments and tongue) without requiring additional separate fastening operations. This self-service characteristic simplifies the assembly process and reduces operational complexity despite the enhanced retention mechanism.
Data Source
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AI summary
A locking blade 100 for a rotor can include an airfoil portion 126 with a root 122 from which a tongue extends 123. Opposed bucket segments 111, 113 can engage the tongue 123 and can be retained in a longitudinal direction of the blade by a fastener 130, such as a pin, that can extend through holes 119 in the segments 111, 113 and tongue 123. Tines 127 parallel to and on opposite sides of the tongue 123 can extend from the root 122 and include holes 129 through which the fastener 130 can extend, the bucket segments 111, 113 extending between respective tines 127 and the tongue 123. The structure 100 can eliminate an assembly gate in a rotor.