Radial Shaft Seal Lip Structure for High-Speed Leakage Return
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Radial shaft seals fail to reliably seal at high rotational speeds due to inefficiencies in return conveying elements, particularly at speeds above 10,000 r.p.m., where leaked medium is not effectively returned to the medium side, leading to leakage issues.
Innovation Solution
The radial shaft seal design incorporates a first circumferentially extending ring with depressions between return conveying elements, which redirects leaked medium back to the medium side, reducing leakage flow and enhancing sealing efficacy by enlarging the contact surface between the ring and shaft, and utilizing symmetrical return conveying elements to ensure reliable medium return in both rotational directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slanted grooves are used as return conveying elements, then medium can be returned to the medium side, but at high rotational speeds (above 10,000 r.p.m.) the medium is not effectively returned leading to leakage
Solution Approach 1:
The first circumferentially extending ring is segmented into multiple elevations distributed about its circumference, creating distinct depressions between them. This segmentation allows the medium to be returned through multiple pathways simultaneously, improving effectiveness at high rotational speeds where single grooves fail
Solution Approach 2:
The invention transitions from two-dimensional slanted grooves to a three-dimensional structure with elevations and depressions. The depressions extend in the axial direction toward the second ring, creating depth and volume that enhance medium return capability at high speeds by providing larger capacity and better flow guidance
2Reliability
If the first ring is designed with elevations and depressions, then the contact surface between the ring and shaft is enlarged reducing leakage, but the structure becomes more complex
Solution Approach 1:
The first circumferentially extending ring serves multiple functions simultaneously: it provides sealing contact with the shaft, returns leaked medium to the medium side, and the elevations structurally support the sealing lip. This multi-functionality reduces the need for additional separate components, offsetting the complexity of the elevation-depression structure
Solution Approach 2:
The invention merges the return conveying function with the sealing ring structure itself by forming elevations and depressions directly on the first ring. This integration eliminates the need for separate return conveying components, reducing overall device complexity while maintaining enhanced sealing effectiveness
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 design effectively seals shafts at high rotational speeds up to 50,000 r.p.m. and beyond, ensuring reliable medium return independent of rotational direction, minimizing leakage, and maintaining low wear and noise levels, making it suitable for electric vehicles and other high-speed applications.
Implementation Method 1
The depressions ensure that medium which has leaked underneath the first ring is returned in the direction toward the medium side
Implementation Method 2
the return conveying elements are formed by grooves that are alternatingly oppositely slanted relative to the circumferential direction of the sealing lip
Data Source
AI summary
A radial shaft seal has an elastomeric sealing lip with an inner side facing a shaft to be sealed. The sealing lip has a first circumferential ring arranged at the inner side and resting against the shaft to seal a medium side from an air side. Return conveying elements are arranged circumferentially about the sealing lip at the inner side and at a side of the first circumferential ring facing the air side. They return leakage medium, independent of a rotational direction of the shaft, to the medium side. A second circumferential ring at the inner side is positioned at a side of the return conveying elements facing the air side. The first circumferential ring is an elevation with depressions, also formed as elevations, distributed circumferentially thereabout. The depressions extend toward the second circumferential ring and are positioned, respectively, between two of the return conveying elements neighboring each other.