Blade Root Interlock Mechanism for Rotating Hub Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing secondary retention devices for rotating blades, such as propeller assemblies, require skilled installation, are prone to vibration and wear due to relative movement, and are difficult to inspect, as they are not integral to the hub or blade and can be overlooked during assembly.
Innovation Solution
A secondary retention device featuring an interlock mechanism where the root part of the blade is coupled to the hub using a retention cavity and threaded or bayonet-style interlock, ensuring radial separation prevention in case of primary retention device failure without requiring skilled assembly and minimizing contact during normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wire is used as a secondary retention device, then radial separation prevention is achieved, but installation complexity increases and inspection difficulty increases
Solution Approach 1:
The secondary retention device is merged with the blade and hub structures. The root part is integrated into the blade root, and the hub part is integrated into the hub, eliminating the need for separate wire installation and ensuring permanent attachment.
Solution Approach 2:
The secondary retention device is segmented into three distinct parts: the root part integrated with the blade root, the retention cavity in the hub, and the hub part in the hub. This segmentation allows for simplified manufacturing and assembly while maintaining reliability.
2Reliability
If a wire is used as a secondary retention device, then radial separation prevention is achieved, but vibration and wear problems occur
Solution Approach 1:
By integrating the root part as an integral part of the blade and the hub part as an integral part of the hub, the invention eliminates relative movement between the secondary retention device components and the blade-hub assembly, thereby preventing vibration and wear.
3Reliability
If a wire is used as a secondary retention device, then radial separation prevention is achieved, but inspection difficulty increases
Solution Approach 1:
The invention provides visual indicators through the interlock mechanism and retention cavity design that allow inspectors to easily detect the presence and proper installation of the secondary retention device, eliminating the concealment issues of wire-based systems.
4Ease of manufacture
If an interlock mechanism is used, then assembly simplicity is improved, but device complexity increases
Solution Approach 1:
The interlock mechanism is segmented into simple geometric features (protrusions and recesses) that can be easily manufactured and assembled, rather than a complex single-piece mechanism. This segmentation reduces manufacturing difficulty while providing the necessary interlocking function.
Data Source
AI summary
A blade assembly including: a hub which is rotatable about an axis; at least one blade having an aerofoil portion and a root, wherein the root is coupled to the hub using a primary retention device which prevents radial separation of the root and hub in normal use; and, a secondary retention device having a root part and a hub part, the root part being located radially inwards of the hub part in a retention cavity in use, wherein at least a portion of the root part enters the retention cavity via an interlock which prevents radial separation of the root and hub in the event of a primary retention device failure.