Concave Bearing Seal Lip Geometry for High-Interference Sealing
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Solution Overview
Problem
Sealing devices for bearing units face inefficiencies due to 'flattening' of contact lips under increased interference, leading to reduced sealing performance and pressure peaks, especially in smaller seating spaces, which complicates the balance between contact force and pressure distribution.
Innovation Solution
The contact lip is optimized with a concave shape, featuring a first radius and adjusted angles to maintain high pressure peaks and flexibility, reducing deformation and flattening effects, and a recess at the base for enhanced flexibility and constant contact force across varying interference values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the interference between contact lip and contact surface is increased to improve sealing performance, then the sealing pressure increases, but the contact lip flattens and the contact area increases which reduces the pressure peak and sealing efficiency
Solution Approach 1:
The contact lip is designed with a concave cross-sectional shape instead of a straight or convex profile. This curvature allows the lip to maintain a smaller contact area even under increased interference conditions, preserving the pressure peak necessary for effective sealing while accommodating larger interference values without flattening.
Solution Approach 2:
The invention modifies the geometric parameters of the contact lip, specifically the angle between the generatrix and the axis (ranging from 45° to 60°), to optimize the balance between contact force and pressure distribution. This parameter optimization enables the lip to withstand higher interference while maintaining sealing effectiveness.
2Stress or pressure
If the contact area of the lip is increased to reduce pressure peaks, then the sealing performance improves under low interference, but under high interference the lip flattens and contact area increases excessively reducing pressure below effective levels
Solution Approach 1:
The concave cross-section of the contact lip creates a geometric configuration where the contact area remains controlled even as interference increases. The curved profile ensures that pressure is concentrated at the deepest point of the concavity, maintaining effective pressure peaks while distributing load to prevent excessive flattening.
3Volume of moving object
If the seating space for the seal is reduced to meet compact design requirements, then the assembly size decreases, but the available space for the contact lip reduces leading to increased flattening and decreased performance
Solution Approach 1:
By optimizing the angular parameter (generatrix angle between 45° to 60°) and the concave profile dimensions, the invention enables the contact lip to function effectively in reduced seating spaces. The optimized geometry allows the lip to achieve sufficient contact pressure and maintain flexibility within tighter spatial constraints.
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 maintains high pressure peaks and sealing performance across a broader range of interference values, delays lip flattening, and increases flexibility, ensuring effective sealing even under severe operating conditions.
Implementation Method 1
The contact lip has a concave shape... reducing deformation and flattening effects
Data Source
AI summary
Sealing device for a bearing unit having at least one contact lip operatively in sliding contact with a contact surface of the bearing unit and in turn provided with a wedge portion which forms with respect to the contact surface a first angle (α) facing a medium to be contained and a second angle (β) opposite the first angle, wherein during operating conditions, the second angle (β) is smaller than the first angle (α) and with a first surface having a concave shape, the concavity of which is defined by a first radius (R1); wherein the second angle (β) is between 48° and 55° and the length of the first radius (R1) is between 2.0 mm and 10.00 mm.