Monolithic Stack Nut Seal Assembly for Gas Turbine Bearing Sealing
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Solution Overview
Problem
Existing seal assemblies in gas turbine engines face inefficiencies due to multiple hardware components creating tolerance stack-ups, leading to reduced seal performance and increased repair costs, with existing solutions often requiring separate air seals and retention methods that can be unreliable during engine operation.
Innovation Solution
A monolithic stack nut with integrally formed air seal features, such as knife-edge or labyrinth seals, which eliminates the need for additional hardware components like key washers and air seal rings, reducing the hardware count and tolerance stack-ups, and enhancing the seal's performance by integrating air seal elements directly into the stack nut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple hardware components (retaining ring, key washer, air seal ring) are used in the seal assembly, then the seal assembly can retain various components, but the stacking of tolerances between different pieces reduces the efficiency of the seal assembly
Solution Approach 1:
The patent combines multiple separate hardware components (stack nut, retaining ring, key washer, air seal ring) into a single monolithic stack nut structure. The monolithic structure integrates the retention function for bearings and the air seal function in one piece, eliminating tolerance stack-up between multiple components while maintaining the ability to retain various hardware components.
2Adaptability or versatility
If separate air seal ring and retention hardware are used, then the seal assembly can perform multiple functions, but the hardware count increases and repair costs increase
Solution Approach 1:
The monolithic stack nut is designed to perform multiple functions simultaneously: it retains bearings through the bearing retention feature, provides air sealing through the air seal feature, and structures the seal assembly. This multi-functional design eliminates the need for separate air seal rings and retention hardware, reducing overall device complexity.
3Ease of operation
If multiple pieces of hardware are stacked to form the seal assembly, then the assembly can be configured with various seal components, but the tolerance stack-up reduces seal performance
Solution Approach 1:
The patent merges multiple stacked hardware components into a single monolithic structure that maintains assembly configuration flexibility through integrated features while eliminating tolerance stack-up. The monolithic design ensures reliable seal performance by providing a continuous, precise sealing surface without the cumulative tolerances of multiple assembled parts.
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 monolithic stack nut design improves seal efficiency by reducing hardware count, minimizing repair costs, and enhancing the air seal's performance by eliminating tolerance stack-ups and undesirable behaviors during engine operation, resulting in a more reliable and effective sealing mechanism.
Implementation Method 1
The air seal land can comprise an abradable portion sealingly engaged with the knife edge seal of the third major portion
Data Source
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AI summary
A seal assembly (88) for a bearing compartment (50B) includes a coupler (90) with a lip (98), seal plate (92), nut (94), and air seal land (96). The seal plate (92) is disposed on and around the coupler (90) and is in contact with the lip (98). The nut (94) is disposed within the bearing compartment (50B) and adjoining the seal plate (92). The nut (94) includes first (102), second (108), and third (116) major portions and first (106) and second (112) intermediate portions. Each of the first (102), second (108), and third (116) major portions is in the shape of an annular band. The second major portion (108) is disposed axially between the first (102) and third (116) major portions. The third major portion (116) includes a knife edge seal (118) extending radially outward. The first (106) and second (112) intermediate portions include frustums and extend between the first (102) and second (108) major portions and second (108) and third (116) major portions, respectively. The air seal land (96) is sealingly engaged with the third major portion (116) of the nut (94).