Dynamic Seal With Floating Counterface For Radial Runout
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Solution Overview
Problem
Radial seals face challenges in maintaining effective sealing contact at high speeds due to positional variations and dynamic run-out, leading to increased friction and uneven wear, as they are typically mounted with small clearance and experience radial load.
Innovation Solution
A dynamic seal design featuring an inner and outer seal part with a floating counterface part that is axially retained by both, allowing for relative radial movements without increasing friction and wear, and incorporating elastomeric sealing elements with micro-lips and arm sections for flexible contact and lubrication, enabling adaptive sealing contact based on friction levels and accommodating axial deflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal is mounted with a very small clearance and the lip is spring-loaded to ensure contact with the counterface, then sealing effectiveness is improved, but radial load on the seal lip increases generating additional friction and uneven wear
Solution Approach 1:
The seal is divided into two independent seal lips (first seal lip and second seal lip) that can operate independently. Each seal lip can be optimized separately - one for sealing contact and the other for load bearing, or both can share the sealing function with reduced individual loads compared to a single spring-loaded lip design.
Solution Approach 2:
The seal design allows the seal lips to dynamically adjust their position and contact force based on operating conditions. The clearance between the seal and counterface is optimized to allow natural contact without excessive spring loading, enabling the seal to adapt to radial movements and eccentricity while maintaining reliable sealing contact.
2Reliability
If the seal lip is spring-loaded to maintain contact with the counterface during dynamic run-out, then sealing contact is maintained, but friction and wear increase due to radial load
Solution Approach 1:
Instead of applying full spring loading to ensure contact under all conditions, the design uses optimized clearance and geometry to achieve sufficient sealing contact with minimal radial load. The seal lips are positioned to naturally maintain contact during normal dynamic run-out without excessive spring force.
Solution Approach 2:
The design changes the critical parameters from spring load force to clearance distance and seal lip geometry. By optimizing the radial clearance and the angle of the seal lips, the system achieves reliable sealing contact while minimizing the radial load that causes friction and wear.
3Reliability
If the seal experiences radial load to maintain contact under dynamic run-out, then sealing is effective, but uneven wear occurs around the lip circumference
Solution Approach 1:
The seal is segmented into multiple seal lips that distribute the sealing function. This segmentation allows each lip to experience more uniform wear patterns and enables the system to accommodate dynamic run-out without concentrating load on specific circumferential locations, thereby extending overall seal lifespan.
Solution Approach 2:
The seal design incorporates dynamic characteristics that allow the seal lips to adapt their contact points during rotation. The optimized clearance and lip geometry enable the seal to naturally follow the counterface profile during dynamic run-out, distributing wear more evenly around the circumference and preventing localized premature failure.
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 seal minimizes wear and extends its lifespan by automatically selecting the sliding contact interface with the lowest friction, maintaining effective sealing while accommodating positional variations and pressure differentials, thus ensuring prolonged performance.
Implementation Method 1
Each of the first and second sealing elements of the inner and outer seal parts are axially enclosed between oppositely oriented axial surfaces of the counterface part
Implementation Method 2
The dynamic seal is adapted to permit an axial displacement of the counterface part relative to the inner and outer members, in a manner which maintains effective sealing between the counterface part and each set of first and second sealing elements
Data Source
AI summary
The present invention provides a dynamic seal for enclosing a radial gap between coaxial, relatively rotatable inner and outer members. The dynamic seal includes an inner seal part, mountable to the inner member; an outer seal part, mountable to the outer member; and a counterface part radially suspended between the inner and outer seal parts and coaxial therewith. Each of the inner and outer seal parts provides a set of first and second sealing elements, which bear against oppositely oriented axial surfaces of the counterface part. The counterface part is thus axially retained in both directions by the inner seal part at a radially inner contact location, and is axially retained in both directions by the outer seal part at a radially outer contact location.