Braided Covers with Variable Tow Properties for Propeller Blade Tips
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Solution Overview
Problem
Existing braiding processes struggle to apply a braided cover uniformly to propeller blades, particularly in the tip region, leading to excess material that needs to be cut, resulting in discontinuities and increased costs.
Innovation Solution
Varying properties of the fibre tows along the length of the bobbins, such as diameter, material, and linear weight, to tailor the braided cover to the shape of the core, allowing for a closer fit and reducing the need for cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a uniform tow configuration is used for braiding the cover, then the braiding process is simple and cost-effective, but the cover does not closely follow the shape of the variable perimeter core, resulting in excess material that must be cut
Solution Approach 1:
The patent applies local quality by varying the tow configuration (number of fibres, diameter, or linear weight) at different positions along the length of the tow, specifically reducing fibres towards the tip region to match the variable perimeter core shape, while maintaining uniform configuration in other regions
Solution Approach 2:
The patent implements parameter changes by modifying physical parameters of the tow such as the number of fibres, tow diameter, or linear weight along the length of the tow, allowing the braided cover to adapt to the changing perimeter of the core without complicating the overall braiding process
2Manufacturing precision
If the tow configuration is optimized to closely follow the core shape, then coverage accuracy improves, but the braiding process becomes more complex and costly
Solution Approach 1:
The variation in tow properties is applied locally rather than uniformly throughout, with changes concentrated in specific regions (e.g., tip region with fewer fibres) while other regions maintain standard configuration, balancing precision with manufacturing simplicity
Solution Approach 2:
The tow is effectively segmented into sections with different properties (e.g., root region with full fibres, tip region with reduced fibres), allowing each section to be optimized for its specific location while maintaining overall process simplicity
3Manufacturing precision
If excess braid material is cut to achieve close engagement, then coverage accuracy improves, but structural integrity is compromised due to discontinuities in the cover fibres
Solution Approach 1:
The tow configuration is pre-adjusted before braiding by varying the number of fibres or diameter along the tow length, so that the correct amount of material is deposited at each location, eliminating the need for post-braiding cutting and preserving structural integrity
Data Source
AI summary
A method of applying a braided cover to a core comprises braiding a plurality of tows around the core from a plurality of bobbins. One or more properties of the tow on a respective bobbin vary along the length of the tow.