Bicycle Shock Absorber Seal Lip Geometry for High-Pressure Friction
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Solution Overview
Problem
Existing sealing assemblies for bicycle shock absorbers face challenges in maintaining effective sealing under high pressures, leading to increased radial load, non-uniform friction, and reduced effectiveness of the dust protection lip.
Innovation Solution
A new oil lip configuration with a flared radial cross-section and optimized dimensional ratios, combined with a rigid annular support and strategically positioned annular ribs, reduces radial load and maintains constant friction even at high pressures, ensuring stable performance of the dust protection lip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high pressure is used inside the shock absorber body, then the sealing effectiveness of the oil lip is improved, but the radial load on the oil lip increases and causes non-uniform friction
Solution Approach 1:
The patent changes the geometric parameters of the oil lip by providing a flared radial cross-section where the radial thickness increases from the inner radius to the outer radius. This parameter modification allows the oil lip to withstand high internal pressures while distributing the radial load more uniformly, thereby maintaining sealing effectiveness without excessive radial load concentration.
Solution Approach 2:
The patent applies local quality by creating a non-uniform radial thickness distribution in the oil lip, with greater thickness at the outer radius compared to the inner radius. This localized variation in geometry provides enhanced structural support where needed (at the outer radius facing high pressure) while maintaining flexibility and sealing contact at the inner radius.
2Reliability
If high pressure acts on the oil lip, then the sealing function is enhanced, but the dust protection lip deforms and loses effectiveness
Solution Approach 1:
The patent modifies the geometric parameters of the seal by implementing a flared radial cross-section in the oil lip portion. This parameter change creates a more stable structural configuration that resists deformation under high pressure, thereby preventing the transmission of excessive radial loads to the dust protection lip and maintaining its stability and effectiveness.
Solution Approach 2:
The patent segments the seal into distinct functional portions: an oil lip with flared radial cross-section for withstanding internal pressure, and a separate dust protection lip for preventing contaminant ingress. This segmentation allows each portion to be optimized for its specific function, with the oil lip absorbing the high pressure loads and protecting the dust protection lip from deformation.
3Reliability
If radial compression springs are added to both sealing lips, then the sealing performance is improved, but the overall size of the sealing assembly increases in the axial direction
Solution Approach 1:
The patent extracts the compression spring from the system by utilizing the flared radial cross-section geometry of the oil lip itself to provide the necessary radial loading and contact pressure. This eliminates the need for separate radial compression springs, thereby maintaining sealing performance while reducing the axial size of the sealing assembly.
Solution Approach 2:
The patent merges the structural support function and the sealing contact function into a single integrated oil lip component with a flared radial cross-section. This consolidation eliminates the need for separate components like radial compression springs, achieving both sealing performance and compact axial dimensions through the unified geometric design.
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 new sealing assembly design effectively reduces radial load and maintains constant friction and dust protection performance even under high pressures, enhancing the overall sealing efficiency and durability.
Implementation Method 1
a body (8) made of an elastomeric material... first and second opposite annular sealing lips (10, 11) which are formed integrally as one piece with the annular body (8)
Implementation Method 2
maintains constant friction even at high pressures
Data Source
AI summary
A sealing assembly for a bicycle shock absorber includes an annular elastomeric body comprising a solid median portion, a first annular sealing lip and a second annular sealing lip. An annular support is at least partially embedded in the elastomeric body. The first annular sealing lip projects radially inward and projects in a first axial direction from a first axial end of the solid median portion, the second annular sealing lip projects radially inward and in a second axial direction from a second axial end of the solid median portion, and the second annular sealing lip is flared in radial cross-section towards a free end of the second annular sealing lip, the free end being opposite a root portion of the second annular sealing lip at the second axial end of the solid median portion.