Rotary Seal Lip Pockets for Recirculation Without Wear
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Solution Overview
Problem
Rotary seals face premature wear and reduced service life due to friction and thermal stress, leading to fluid leakage and compromised recirculation function, especially under high pressures and sliding speeds.
Innovation Solution
The rotary seal arrangement features a sealing lip with pockets on its rear side, which are tensioned by an elastic pretensioning ring, allowing for fluid recirculation without direct mechanical contact with the dynamic sealing surface, reducing wear and enhancing sealing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tribo structures are added to the front side of sealing lips to enable fluid recirculation, then recirculation function is improved, but wear increases and service life decreases
Solution Approach 1:
The patent inverts the conventional approach by moving the recirculation function from the front side (sealing side) to the rear side of the sealing lip. The pockets are formed on the rear side, allowing fluid recirculation without requiring wear-prone structures on the sealing surface, thus preserving service life while maintaining recirculation capability
Solution Approach 2:
The patent transitions the recirculation mechanism from a two-dimensional surface structure to a three-dimensional pocket structure on the rear side of the sealing lip. This dimensional change allows fluid to be redirected through depth rather than surface features, eliminating wear on the sealing face while maintaining recirculation
2Reliability
If sealing pressure is increased to maintain sealing capacity under high operating pressures, then sealing capacity is improved, but friction and thermal stress increase
Solution Approach 1:
The pockets on the rear side of the sealing lip act as an intermediary mechanism that reduces the direct relationship between sealing pressure and friction/thermal stress. By enabling fluid recirculation through the pockets, the system can maintain sealing capacity without proportionally increasing friction and heat generation
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
This design ensures efficient fluid recirculation over extended periods, reduces leakage, and mitigates thermal stress, while maintaining sealing capacity even at higher operating pressures and velocities.
Implementation Method 1
The rotary seal is designed as a radial shaft sealing ring, which is tensioned by an elastically, preferably rubber-elastic, deformable pretensioning ring against the sealing surface
Data Source
AI summary
A rotary seal assembly has a first and second machine element spaced apart forming a sealing gap. The first machine element has a seal-holding structure and the second machine element a sealing surface. A rotary seal is held on the seal-holding structure of the first machine element which has a sealing lip, the front side of which faces the sealing surface and at least partially abuts the sealing surface of the second machine element, pretensioned in a dynamically sealing manner. The sealing lip has pockets on its rear side or on its end face facing the high pressure side. The sealing lip on its rear side, in the case of rearwardly arranged pockets, is tensioned against the sealing surface by an elastically deformable pretensioning ring, and is tensioned in the case of the front side pockets by an elastic resilience inherent in the material of the rotary seal.