Universal Joint Seal Carrier Ring Form-Fit Engagement
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Solution Overview
Problem
Conventional seals for cross member units in universal joints face challenges in providing a secure and effective connection between the carrier ring and the elastomeric sealing lip element, particularly when made of different materials like thermoplastic and elastomer, which can lead to separation issues due to low adhesive properties.
Innovation Solution
The seal features a carrier ring with an L-shaped cross section and an elastomeric sealing lip element that engages through form-fitting elements in different directions, including axial and radial apertures, enhancing the connection by providing resistance against separation in both directions, and utilizing projections for a press fit and centered positioning within the bearing cup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional seals use simple attachment methods between carrier ring and elastomeric sealing lip element, then manufacturing is easier, but connection reliability deteriorates due to separation issues between different materials
Solution Approach 1:
The attachment structure is segmented into multiple engagement elements distributed around the carrier ring circumference, with each element providing localized form-fitting engagement. This segmentation distributes the mechanical stress and prevents single-point failure, thereby improving connection reliability between the thermoplastic carrier ring and elastomeric sealing lip element.
Solution Approach 2:
The engagement elements exhibit local quality variations with different geometries optimized for specific engagement directions. Some elements feature axial engagement portions while others provide radial engagement, creating locally optimized attachment points that collectively enhance overall connection reliability without requiring uniform complex structures throughout.
2Reliability
If the seal uses form-fitting engagement elements in multiple directions, then resistance to separation improves, but manufacturing precision requirements increase
Solution Approach 1:
The engagement elements are designed with preliminary action features that guide the assembly process. The form-fitting geometry includes tapered or guided portions that automatically align the elastomeric sealing lip element with the carrier ring during installation, reducing the actual precision required during final engagement and compensating for normal manufacturing tolerances.
Solution Approach 2:
The engagement elements utilize parameter changes in material properties and geometric dimensions to accommodate manufacturing variations. The elastomeric material's flexibility and the thermoplastic's dimensional stability are leveraged to create engagement tolerances that maintain reliable connection while being achievable with standard manufacturing precision.
3Manufacturing precision
If the carrier ring uses projections for press fit and centering, then positioning accuracy improves, but device complexity increases
Solution Approach 1:
The projections on the carrier ring serve multiple functions simultaneously: they provide press-fit engagement with the bearing cup for axial positioning, radial centering through circumferential distribution, and structural reinforcement for the thermoplastic material. This multi-functionality achieves high positioning accuracy without adding separate centering mechanisms, thereby limiting complexity increase.
Data Source
AI summary
A seal for a cross member unit for universal joints has a carrier ring to be inserted into a bearing cup of the cross member unit. The carrier ring has an L-shaped cross section with a cylindrical portion coaxial to a longitudinal axis and a flange portion extending form the cylindrical portion inwardly. An elastomeric sealing lip element is connected to the carrier ring. The sealing lip element has first engagement elements form fittingly engaging into first engagement apertures. The first engagement apertures extend through the flange portion of the carrier ring. The sealing lip element further has second engagement elements form fittingly engaging into second engagement apertures. The second engagement apertures extend through the cylindrical portion of the carrier ring.