Modular Labyrinth Seal Fins for Precise Gearbox Clearance Control
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Solution Overview
Problem
Existing labyrinth seals in aircraft engine oil systems face challenges in controlling clearance between fins due to material properties and machining limitations, leading to leakage and operational difficulties.
Innovation Solution
The aircraft engine labyrinth seal employs attachable fins formed from different materials, such as metallic and polymeric materials, with attachment methods like press-fitting, welding, gluing, bolting, and riveting, to precisely control clearances and improve structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional labyrinth seals are made as single integrated pieces from uniform materials, then manufacturing is simpler, but clearance control precision deteriorates due to material properties and machining limitations
Solution Approach 1:
The labyrinth seal is divided into multiple separate components (fins) that can be manufactured independently and then assembled to the seal base. This segmentation allows each fin to be precisely manufactured with controlled dimensions and then positioned with accurate clearances during assembly, overcoming the machining limitations of monolithic seals.
Solution Approach 2:
The seal assembly uses different materials for the seal base and the fins. The fins can be made from materials with different thermal expansion coefficients and mechanical properties, allowing optimization of clearance control under thermal conditions while maintaining structural integrity.
2Ease of repair
If labyrinth seal fins are made as integrated parts, then structural integrity is maintained, but repair and replacement difficulty increases
Solution Approach 1:
The fins are designed as separate, detachable components that can be individually removed and replaced without affecting the seal base or other fins. This modular design enables easy maintenance and repair while the attachment methods ensure structural integrity during operation.
Solution Approach 2:
The fins are pre-manufactured to precise specifications and pre-assembled with proper clearance control before installation. This preliminary preparation ensures that when replacement is needed, the new fins can be directly installed without complex adjustment procedures, maintaining both ease of repair and structural integrity.
3Reliability
If contact seals are used to seal around rotating shafts, then fluid sealing is achieved, but rubbing contact interface creates wear and operational difficulties in high-temperature environments
Solution Approach 1:
The invention extracts the contact interface between seal and rotating shaft, replacing it with a non-contact labyrinth structure. The fins create a tortuous path that prevents fluid leakage without physically contacting the rotating shaft, eliminating wear and extending service life in high-temperature environments.
Solution Approach 2:
The mechanical contact-based sealing system is replaced with a fluid dynamic sealing system using the labyrinth structure. The sealing effect is achieved through pressure differential and viscous forces in the narrow gaps between fins and the rotating shaft, rather than mechanical contact.
Data Source
AI summary
An aircraft engine stationary labyrinth seal assembly is provided for use in a gearbox of an aircraft engine oil system. The aircraft engine stationary labyrinth seal includes a stationary part defining an opening, a rotatable part, which is rotatable relative to the stationary part within the opening, a seal base and a labyrinth seal fin member. The seal base is affixable to the stationary part. The seal base includes an interior facing annular mating portion. The labyrinth seal fin member includes exterior facing annular mating portion attachable to the interior facing annular mating portion and an interior facing annular labyrinth seal including multiple prongs configured to cooperatively form a stationary labyrinth seal with the rotatable part.