Rotor Blade Retention Assembly for Compact Hub Removal
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Solution Overview
Problem
Existing rotor blade retention assemblies in rotary propulsor systems require complex disassembly processes for blade removal, necessitate larger hub components, and compromise aerodynamic efficiency due to less compact designs.
Innovation Solution
A rotor blade retention assembly that utilizes a tension-torsion strap coupled to a hub arm via lugs, allowing for blade removal without disassembling the hub top plate or seals, and reduces the hub radius, enabling a more compact and aerodynamic design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If existing rotor blade retention assemblies are used, then blade retention is achieved, but complex disassembly processes are required for blade removal
Solution Approach 1:
The retention assembly is divided into separate modular components: the hub assembly with hub arms, the blade with blade root, and the tension-torsion straps. This segmentation allows the blade to be removed by detaching only the strap connections rather than disassembling the entire hub structure, simplifying the removal process while maintaining secure retention during operation.
Solution Approach 2:
The tension-torsion straps are extracted as separate removable components that can be independently detached from the hub and blade. By extracting the retention function into these dedicated straps rather than integrating it into the hub structure itself, the blade can be removed without disturbing the hub top plate or seals.
2Weight of moving object
If existing rotor blade retention assemblies are used, then blade retention is achieved, but larger hub components are necessitated
Solution Approach 1:
The tension-torsion straps serve as intermediary elements that transfer and distribute the blade retention loads to the hub arms. These straps act as flexible mediators that can accommodate the high strength requirements for blade retention while allowing the hub structure itself to be more compact and lighter, as the straps bear the primary retention loads rather than requiring the hub to be oversized for direct blade attachment.
3Shape
If existing rotor blade retention assemblies are used, then structural integrity is maintained, but aerodynamic efficiency is compromised
Solution Approach 1:
By segmenting the retention system into separate hub arms and tension-torsion straps, the design allows for a more compact hub radius and cleaner aerodynamic contours. The segmented structure eliminates the need for large integrated hub components that would disrupt airflow, while each segment (strap and hub arm connection) is designed to maintain structural integrity under operational loads.
Solution Approach 2:
The tension-torsion straps function as flexible structural elements that can be made from composite materials with high strength-to-weight ratios. These thin, flexible straps provide the necessary structural integrity for blade retention while occupying minimal space and creating minimal aerodynamic interference, allowing the rotor assembly to achieve more aerodynamic blade shapes and hub contours.
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
Facilitates easier blade removal, reduces hub weight, and enhances aerodynamic performance by allowing more aerodynamic blade shapes, while resisting centrifugal forces effectively.
Implementation Method 1
resisting centrifugal forces effectively
Data Source
AI summary
A rotor blade retention assembly is configured to connect a rotor blade to a central hub comprising a hub arm coupled to and extending radially outward from a hub bowl. The hub arm includes a hub arm lug. The rotor blade retention assembly includes a tension-torsion strap with an inboard end and an outboard end, the inboard end including an inboard pin hole and the outboard end including an outboard pin hole. The rotor blade retention assembly further includes an inboard blade pin and an outboard blade pin. The inboard blade pin is configured to extend through the hub arm lug and the inboard pin hole and to couple the inboard end of the tension-torsion strap to the hub arm. The outboard blade pin is configured to extend through a blade lug of a rotor blade and the outboard pin hole and to couple the outboard end of the tension-torsion strap to the rotor blade.