Seal Assembly Geometry for Gaps Between Movable Components
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Solution Overview
Problem
Conventional seals are inadequate for sealing gaps between relatively movable components, particularly in aerospace applications where space is limited and aerodynamics are a concern, as they often fail to provide effective sealing and can compromise aerodynamic performance.
Innovation Solution
A seal assembly comprising a rub strip and a seal strip with convex and concave engagement surfaces, respectively, where the seal strip is harder and more compressible, and includes internal stiffeners and retainment elements to maintain a seal as the components move relative to each other, facilitating a scissoring motion to maintain contact and seal effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional seals are used to seal gaps between relatively movable components, then sealing function is provided, but the seal performance deteriorates under limited space and aerodynamic constraints
Solution Approach 1:
The seal assembly is divided into two distinct strips: a rub strip fixed to the first component and a seal strip fixed to the second component. This segmentation allows each strip to perform its specific function independently while working together to maintain the seal during relative movement, resolving the contradiction between seal performance and space constraints.
Solution Approach 2:
The rub strip acts as an intermediary element between the two movable components. Instead of directly sealing against each other, the components interact through the rub strip, which provides a controlled engagement surface. This intermediary approach maintains effective sealing while reducing the required gap space and improving aerodynamic performance.
2Reliability
If conventional seals contact directly against opposing primary structure, then sealing is achieved, but aerodynamic performance is compromised
Solution Approach 1:
The engagement surfaces of both the rub strip and seal strip are designed with specific local qualities: convex shapes on the seal strip and corresponding concave/convex surfaces on the rub strip. These localized geometric features concentrate the sealing function at specific contact points while minimizing the overall profile, thereby maintaining aerodynamic performance while ensuring reliable sealing.
3Strength
If seal strip is made harder for durability, then wear resistance improves, but compressibility decreases
Solution Approach 1:
The seal strip is designed with a durometer hardness parameter specifically optimized to balance wear resistance and compressibility. By controlling the hardness parameter within a specific range, the seal strip maintains sufficient softness to deform and conform to the rub strip engagement surface during relative movement, ensuring continuous contact and effective sealing while providing adequate durability.
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
The seal assembly effectively maintains a seal between movable components, even under conditions of limited space and varying motion, enhancing aerodynamic performance by ensuring consistent contact and reducing the need for additional components in the sealing gap.
Implementation Method 1
the seal strip engagement surface is harder than the rub strip engagement surface... the seal strip is more compressible than the rub strip
Data Source
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AI summary
Disclosed herein is a seal assembly (130) for sealing a gap (178) between a first component (120) and a second component (121) is disclosed. The second component (121) is movable relative to the first component (120). The seal assembly (130) includes a rub strip (132) and a seal strip (134). The rub strip (132) includes a seal strip engagement surface (140) having a convex shape. Additionally, the rub strip (132) includes a first component engagement surface (144) that is opposite the seal strip engagement surface (140) and has a concave shape. The seal strip (134) includes a rub strip engagement surface (142) having a convex shape. Furthermore, the seal strip (134) includes a second component engagement surface (146) that is opposite the rub strip engagement surface (142) and has a concave shape. The seal strip engagement surface (140) is harder than the rub strip engagement surface (142).