Conical Metal Ring Seal for Dust-Shielded Rotary Interfaces
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Solution Overview
Problem
Existing sealing technologies for rotary actuators in space-based applications, particularly in abrasive media environments, fail due to ingress of soil or dust particles and thermal extremes, which cause coefficient of thermal expansion (CTE) mismatches between materials.
Innovation Solution
A shielding apparatus comprising a flat metallic ring, typically made of stainless steel, preloaded into a conical shape between the rotary and stationary housings of a rotary actuator. The metallic ring is dry film lubricated with Molybdenum Disulphide and is designed to remain in contact with the housings during rotary motion, preventing abrasive media ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a combination of energized polymer seal and cloth wiper with labyrinth path is used to seal a rotary actuator, then sealing performance is improved, but the seal fails under thermal extremes and abrasive media due to CTE mismatch between materials
Solution Approach 1:
The patent changes the material parameter from polymer/cloth to metal (stainless steel), which has superior thermal stability and consistent CTE properties under thermal extremes, resolving the reliability issue while maintaining sealing effectiveness
Solution Approach 2:
The patent uses a composite structure combining metal ring with dry film lubricant coating, creating a material system that leverages both the thermal stability of metal and the low-friction properties of the lubricant layer for enhanced performance under harsh conditions
2Reliability
If a combination of energized polymer seal and cloth wiper with labyrinth path is used to seal a rotary actuator, then sealing performance is improved, but the seal fails under abrasive media due to CTE mismatch between materials
Solution Approach 1:
The patent changes the material from polymer/cloth to metal, which offers superior resistance to abrasive media and maintains dimensional stability, preventing ingress while withstanding thermal and mechanical stresses
Solution Approach 2:
The patent employs a simple metal ring design that can be easily replaced if worn, using a durable but potentially consumable component rather than a complex multi-material seal system
3Reliability
If a flat metallic ring is preloaded into a conical shape between rotary and stationary housings, then prevention of abrasive media ingress is achieved, but the structure requires precise deformation control
Solution Approach 1:
The patent pre-loads the metal ring into a conical shape during assembly, creating a predetermined deformation that ensures proper sealing contact when the actuator operates, eliminating the need for complex real-time adjustment mechanisms
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 metallic ring effectively prevents the ingress of abrasive media and is less sensitive to thermal extremes, thereby enhancing the operational life and reliability of rotary actuators in harsh environments.
Implementation Method 1
The metallic ring is dry film lubricated with Molybdenum Disulphide
Implementation Method 2
The flat metallic ring is preloaded into a conical shape when installed between the rotary housing and the stationary housing
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
An apparatus for shielding a rotary interface to prevent ingress of abrasive media is provided. The apparatus includes a flat metallic ring (108) that is installed between a rotary housing (102) containing a rotating component and a stationary housing (104) containing a stationary component configured to interface with the rotating component to provide rotational motion. The rotary housing is configured to couple to the stationary housing and rotate with respect to the stationary housing when coupled. The flat metallic ring is preloaded into a conical shape when installed between the rotary housing and the stationary housing.