Self-Retained Variable Vane Linkage With Single-Shear Bell Cranks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing double-shear designs in variable vane assemblies of gas turbine engines require numerous parts and shear interfaces, leading to increased costs and assembly time due to wear and frictional forces.
Innovation Solution
A self-retained linkage system is introduced, where an even or odd number of bell cranks are secured to a self-retained linkage via a single shear interface, reducing the number of parts and shear surfaces by using studs inserted in alternating directions, eliminating the need for additional bolts and bushings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a double-shear design with bolts and bushings is used to connect linkages, then wear control between parts is improved, but the number of parts and assembly time increase
Solution Approach 1:
The patent combines the bushing and the linkage interface into a single integrated component. The self-retained linkage incorporates the bushing function directly into the linkage arm structure, eliminating the need for separate bushing components while maintaining the wear control function through the self-retained design mechanism.
Solution Approach 2:
The patent extracts and eliminates unnecessary components from the traditional double-shear design. By removing separate bushings and retaining only the essential linkage structure with self-retained features, the design reduces part count while preserving the necessary wear control functionality through the self-retained mechanism.
2Strength
If a double-shear design with multiple bolts and retaining means is used, then connection strength is improved, but assembly time and costs increase
Solution Approach 1:
The patent merges multiple fastening functions into a single self-retained linkage component. The integrated design combines the linkage arm, bushing, and retention features into one piece, eliminating the need for multiple separate bolts and retaining means while maintaining adequate connection strength for the application.
Solution Approach 2:
The patent employs a simpler, more economical linkage design that accepts reduced connection strength requirements in exchange for significantly reduced assembly time and cost. The self-retained linkage uses basic machining operations rather than complex multi-component fastening systems, making it suitable for applications where moderate strength is sufficient.
3Reliability
If numerous parts are used in linkage connections, then reliability and wear control are improved, but manufacturing costs increase
Solution Approach 1:
The patent combines multiple functional components into a single self-retained linkage part. The integrated design incorporates the linkage arm, bushing, and self-retention features into one manufacturable component, reducing the total number of parts that need to be manufactured, inventoried, and assembled while maintaining wear control functionality.
Solution Approach 2:
The self-retained linkage is designed as a universal component that performs multiple functions simultaneously: it provides the linkage mechanism, incorporates wear control through the self-retained bushing interface, and ensures retention without additional fasteners. This multi-functionality reduces the overall part count and manufacturing complexity.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A variable vane assembly (70) for a gas turbine engine (20), the variable vane assembly including: a plurality of vanes (72) arranged into a plurality of stages (74, 76, 78, 80), each one of the plurality of vanes being configured for rotation about an axis (82) through movement of a vane arm (84) secured to each one of the plurality of vanes at one end and a sync ring (86) of each one of the plurality of stages at another end; and a plurality of bell cranks (88, 96) operably coupling the sync ring of each one of the plurality of stages to a self-retained linkage (94) via a stud (106) of each one of the plurality of bell cranks, the stud of each one of the plurality of bell cranks being rotatably received in a corresponding opening of the self-retained linkage in an alternating fashion such that only a single shear interface is provided between each one of the plurality of bell cranks and the self-retained linkage.