Vane Arm Clip for Gas Turbine Variable Stator Vanes
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Solution Overview
Problem
Newer compressor designs in gas turbine engines result in higher compression ratios and increased vane arm strength requirements, which are difficult to meet with traditional sheet metal vane arm designs, especially due to significant forces applied to variable stator vanes.
Innovation Solution
A variable vane actuation system featuring a stem section with a groove, a vane arm with a claw section and clip, and a fastener to retain the clip and vane arm to the stem section, utilizing a clip with an aperture and curved fingers for enhanced strength and interference fit, and manufactured from sheet metal 1.0-1.8 mm thick material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional sheet metal vane arm designs are used, then manufacturing simplicity is maintained, but strength and resistance to rotation forces are insufficient for newer compressor designs
Solution Approach 1:
The vane arm structure is divided into multiple components: a claw section (160) formed from sheet metal and a separate clip (190) that attaches to the claw section. This segmentation allows each component to be optimized independently - the claw section provides the basic structural framework while the clip adds reinforcement specifically at critical stress points, thereby increasing overall strength without requiring complete redesign of the entire vane arm structure.
Solution Approach 2:
The invention combines different materials and structural forms to create a composite vane arm assembly. The claw section is formed from sheet metal (40-70 mils thick), while the clip is also made from sheet metal but designed with a different geometry (full hoop with slot or partial hoop) to provide complementary structural support. This composite approach allows the assembly to achieve higher strength requirements while maintaining the manufacturing advantages of sheet metal construction.
2Strength
If sheet metal thickness is increased to meet strength requirements, then manufacturing precision is maintained, but weight and material usage increase
Solution Approach 1:
Instead of increasing the thickness of the entire vane arm structure, the design segments the reinforcement function into a separate clip component. The original claw section maintains its standard sheet metal thickness (40-70 mils), and only the clip portion adds additional material. This localized addition of material provides the necessary strength increase while minimizing overall material usage compared to uniformly thickening the entire structure.
Solution Approach 2:
The clip is designed to provide reinforcement specifically at the critical interface between the vane arm and the stem section, where stress concentrations occur during operation. The clip's geometry (full hoop with slot opposite the aperture or partial hoop) is optimized to provide local structural support exactly where needed, rather than uniformly increasing material throughout the entire vane arm structure.
Data Source
AI summary
A variable vane actuation system for a gas turbine engine includes a stem section, along an axis, the stem section includes a groove; a vane arm comprising a claw section received at least partially into the groove; a clip mounted to the claw section; and a fastener fastened to the stem section along the axis to retain the clip and the vane arm to the stem section.