Pre-Strained S-Shaped Seal Assembly for Flexible Joints
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Solution Overview
Problem
Conventional seal assemblies for flexible joints, such as those in off-highway machines, experience reduced service life due to deformation during pivotal movements, and radial swaging methods are costly and insufficient for all applications.
Innovation Solution
A seal assembly with a seal body having a generally S-shaped cross-section, defined by an inner and outer surface, and a center section, which is pre-strained by axial displacement to reduce strain during operation, with specific height-to-thickness and offset-to-height ratios optimizing flexibility and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional seal assemblies are used with radial swaging, then some seal strain is reduced, but the manufacturing complexity increases and cost increases
Solution Approach 1:
The seal body is pre-formed with an S-shaped cross-section configuration before installation. This preliminary shaping creates pre-strain in the seal material that counteracts the strain experienced during pivotal movements, eliminating the need for post-manufacturing radial swaging operations and reducing manufacturing complexity
Solution Approach 2:
The invention changes the geometric parameters of the seal body by creating an S-shaped cross-section with specific height-to-thickness ratios (3:1 to 9:1) and offset distances (3-22mm). This parameter optimization provides inherent strain reduction capability without requiring additional manufacturing steps like radial swaging
2Strength
If the seal body is made thicker to withstand deformation, then strength increases, but flexibility decreases
Solution Approach 1:
The invention optimizes the height-to-thickness ratio parameter to fall within 3:1 to 9:1, and the offset distance parameter to fall within 3-22mm. These parameter ranges create a seal body that is thick enough to withstand deformation forces while maintaining sufficient flexibility through the S-shaped geometry that distributes stress evenly
Solution Approach 2:
The S-shaped cross-section introduces curvature to the seal body geometry. This curved configuration allows the seal to flex and deform more easily during pivotal movements while maintaining structural integrity, effectively balancing strength and flexibility requirements
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 pre-strained S-shaped seal body significantly reduces strain and extends service life by accommodating pivotal movements while maintaining effective debris protection, as demonstrated by finite element analysis.
Implementation Method 1
The seal assemblies deform during the transverse, pivotal movement which may curtail the service life of the seal assemblies
Data Source
AI summary
A seal assembly (52) and method of forming a seal assembly (52) provides a seal body (56) having reduced strain during use, thereby increasing service life. The seal body (56) may be formed within certain parameters, such as ranges of height-to-thickness and offset-to-height ratios, which have been found to reduce strain. Additionally or alternatively, the seal body (56) may be modified from an initial configuration to a pre-strained configuration by axially displacing an inner section of the seal with respect to an outer section of the seal, which also reduces strain.