Propeller Shaft Zero Air Gap Seal Removal via Radial-Axial Pulling
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Solution Overview
Problem
Existing propeller shaft seals in aircraft systems wear out and leak lubricant, causing customer dissatisfaction and environmental issues, necessitating improved sealing solutions.
Innovation Solution
A removal tool assembly is designed to radially and axially remove the outer seal from the bearing housing while the inner seal remains in place, utilizing a combination of seal holders, radial reaction pullers, and axial flanges to create a gap between the seals, allowing for efficient disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer seal is tightly fitted in the bearing housing to prevent leakage, then sealing performance is improved, but the seal becomes difficult to remove for maintenance
Solution Approach 1:
The seal removal tool is divided into multiple functional components: seal holders that engage with the outer seal, radial reaction pullers that apply radial force, and axial pullers that apply axial force. This segmentation allows the tool to systematically overcome the tight fit through controlled radial and axial forces, enabling removal without damaging the seal or housing.
Solution Approach 2:
The tool first applies radial force through the radial reaction pullers to create radial clearance between the outer seal and bearing housing before applying axial removal force. This preliminary radial action reduces the interference fit, making subsequent axial removal possible and preventing seal damage during the removal process.
2Reliability
If the seal is tightly fitted to prevent lubricant leakage, then sealing reliability is improved, but the seal generates high interference forces during installation and removal
Solution Approach 1:
The radial reaction pullers are engaged first to apply radial force that creates clearance between the outer seal and housing. This preliminary radial action reduces the radial interference force before the axial pullers are engaged to apply removal force, thereby reducing the total interference force required for seal removal.
Solution Approach 2:
The removal force is segmented into radial and axial components applied by separate tool mechanisms. The radial reaction pullers handle radial clearance, while the axial pullers handle removal. This segmentation allows the tool to overcome interference forces more efficiently than a single-direction pull would require.
3Ease of repair
If a traditional seal removal tool is used, then the seal can be removed, but the tool structure is complex and difficult to operate
Solution Approach 1:
The tool is segmented into modular components: seal holders with threaded rods, radial reaction pullers with flanges, and axial pullers with handles. Each component performs a specific function and can be independently positioned or removed. This modularity simplifies the overall structure compared to monolithic tools while maintaining effective seal removal capability.
Solution Approach 2:
The seal holders with threaded rods serve multiple functions: they provide a mounting interface for the radial reaction pullers, transmit radial force, and can be independently adjusted. The radial reaction pullers also serve as mounting points for the axial pullers. This multi-functionality reduces the number of separate components needed, simplifying the overall tool structure.
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 tool assembly effectively disassembles the outer seal, eliminating interference and enabling its removal from the bearing housing, thus addressing the leakage issues and improving maintenance efficiency.
Implementation Method 1
tightening the radial pulling nut onto the holder rod pulls the seal holder and the outer seal radially outwardly
Implementation Method 2
Tightening the puller bolt against the tool plate generates an axial pulling load on the radial reaction puller
Data Source
AI summary
A removal tool assembly for a shaft bearing seal including a rotating inner seal element and a stationary outer seal includes a first tool portion configured to radially move the outer seal radially outwardly to create a radial gap between the outer seal and the inner seal element disposed at a shaft, and a second tool portion operably connected to the first tool portion. The second tool portion is configured to axially remove the outer seal from a bearing housing while the inner seal element remains in the bearing housing.