Tapered Anti-Rotation Lug for Vane Assembly Installation
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Solution Overview
Problem
The installation of stator vane assemblies in gas turbine engines is prone to human error due to the complexity of aligning anti-rotation lugs and slots, which can lead to improper assembly and potential operational issues.
Innovation Solution
The design incorporates a tapered anti-rotation lug that fits into a tapered second slot, with the aft edge of the aft flange forming an aft wall of the second slot, ensuring the vane cluster is positioned correctly adjacent to the radially inner surface of the engine case, and the anti-rotation lug is directed from the forward flange toward the aft flange of the outer shroud, preventing incorrect installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional anti-rotation lug and slot alignment is used, then the vane assembly can be installed, but human error leads to improper assembly and potential operational issues
Solution Approach 1:
The anti-rotation lug features a tapered geometry with a narrow end and a wide end, creating an asymmetric shape that only fits into the slot from one direction. The slot is correspondingly asymmetric with a narrow opening at the forward end and a wider opening at the aft end, preventing incorrect installation orientations and eliminating alignment errors.
Solution Approach 2:
The tapered geometry of the anti-rotation lug and slot is designed beforehand to guide proper alignment during installation. The narrowing geometry预先 (in advance) directs the installation direction, so that when the lug is inserted into the slot, the correct orientation is automatically achieved without requiring additional alignment steps or human judgment.
2Reliability
If proper alignment features are added to prevent installation errors, then assembly reliability improves, but the device structure becomes more complex
Solution Approach 1:
The anti-rotation function and the alignment guidance function are merged into a single tapered lug-slot feature. Instead of adding separate alignment pins, keys, or marking systems, the tapered geometry simultaneously provides both the anti-rotation capability and the installation guidance, avoiding additional structural complexity.
Solution Approach 2:
The tapered anti-rotation lug serves multiple functions: it prevents rotation, guides alignment during installation, and indicates the correct installation direction. This multi-functional design eliminates the need for separate features for each function, maintaining structural simplicity while improving installation reliability.
3Reliability
If the anti-rotation lug is made asymmetric with tapered geometry, then incorrect installation is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The tapered geometry uses gradual parameter changes in the dimensions of the lug and slot, transitioning from the narrow end to the wide end. This gradual change allows for standard manufacturing tolerances while still achieving the anti-rotation function, as the taper provides a self-aligning feature that compensates for minor dimensional variations.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A vane assembly (100) may comprise an engine case (140) and an anti-rotation lug (144) coupled to the engine case (140). The anti-rotation lug (144) may have a forward end (146) and an aft end (148). A vane cluster (112; 212; 312) may be supported within the engine case (140). The vane cluster (112; 212; 312) may include an outer shroud (132; 232; 332) with a first slot (134a; 234a) defined by a forward flange (172; 272; 372) of the outer shroud (132; 232; 332) and with a second slot (134b; 234b) defined by an aft flange (174; 274; 374) of the outer shroud (132; 232; 332). The second slot (134b; 234b) may be configured to receive the aft end (148) of the anti-rotation lug (144) from a first direction (D1) and wherein the aft flange (174; 274; 374) may be configured to block receipt of the anti-rotation lug (144) from a second direction (D2), which is opposite the first direction (Dl).