Modular Rotary Labyrinth Seal for Aircraft Gearbox Clearance Control
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Solution Overview
Problem
Conventional contact seals in high-speed rotating shafts of aircraft engine oil systems face challenges in controlling clearance due to material properties and machining limitations, leading to leakage and operational difficulties.
Innovation Solution
The aircraft engine rotary labyrinth seal employs a design with attachable fins that can be press-fitted, welded, glued, bolted, or riveted to the base, using different materials for the seal base and fins to precisely control clearances and improve structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional contact seals are used in high-speed rotating shafts, then a fluid seal can be formed through the rubbing contact interface, but clearance control becomes difficult due to material properties and machining limitations
Solution Approach 1:
The seal is divided into separate modular components: a seal base and attachable fins. This segmentation allows the fins to be manufactured separately with precise dimensions and then attached to the base, enabling better clearance control without being constrained by single-piece machining limitations. The fins can be precisely formed and then mounted with controlled positioning relative to the rotating shaft.
Solution Approach 2:
The seal design incorporates attachable fins that can be positioned and adjusted relative to the seal base. This dynamic assembly approach allows for precise clearance control by positioning the fins at specific distances from the shaft surface, overcoming the static limitations of conventional monolithic seal designs that rely solely on machining precision.
2Reliability
If conventional contact seals are used, then sealing function is provided, but operational difficulties arise in high-temperature environments
Solution Approach 1:
The seal employs different materials for the seal base and the fins. The base can be made from a material suitable for high-temperature structural support, while the fins can be made from a material optimized for sealing performance at elevated temperatures. This composite material approach allows each component to be selected for its optimal temperature resistance properties, improving overall reliability in high-temperature environments.
3Ease of repair
If the seal base and fins are made as a single piece, then structural integrity is simplified, but repair and replacement of worn parts becomes difficult
Solution Approach 1:
The seal is designed as segmented modular components with the fins attachable to the seal base through various methods (press-fitting, welding, gluing, bolting, or riveting). This segmentation enables the fins to be replaced independently when worn, without requiring replacement of the entire seal assembly or the base, thus significantly improving ease of repair while maintaining structural integrity through proper attachment methods.
Data Source
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AI summary
An aircraft engine rotary labyrinth seal assembly (101) is provided for use in a gearbox of an aircraft engine oil system. The aircraft engine rotary labyrinth seal (150) includes a stationary part (110) defining an opening (111), a rotatable part (120), which is rotatable relative to the stationary part (110) within the opening (111), a seal base (130) and a labyrinth seal fin member (140). The seal base (130) is affixable to and rotatable with the rotatable part (120). The seal base (130) includes an exterior facing annular mating portion (131). The labyrinth seal fin member (140) is rotatable with the seal base (130) and includes an interior facing annular mating portion (141) attachable to the exterior facing annular mating portion (131) and an exterior facing annular labyrinth seal (142). The exterior facing annular labyrinth seal (142) includes multiple prongs (143) configured to cooperatively form a rotary labyrinth seal (150) with the stationary part (110).