Axially Oriented Fiber Seal for Shock Absorber Wear
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Solution Overview
Problem
Existing seal members for fluid pressure apparatuses face a challenge in improving wear resistance of lip portions without increasing friction and interfering with the smooth movement of rods, as high-hardness elastic materials used to enhance wear resistance also increase modulus of elasticity and tightness, leading to increased friction.
Innovation Solution
The seal member incorporates an elastic body with fibers oriented in the axial direction, specifically using polytetrafluoroethylene (PTFE) fibers, to increase axial modulus of elasticity and hardness while maintaining low radial and circumferential modulus, thereby enhancing wear resistance without increasing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lip portions are formed by using an elastic body having high hardness to improve wear resistance, then the wear resistance of the lip portions is improved, but the modulus of elasticity of the lip portions is increased, leading to increased friction and interference with smooth rod movement
Solution Approach 1:
The patent applies local quality by orienting fibers specifically in the axial direction within the elastic body of the lip portions. This creates anisotropic properties where the material has high stiffness and wear resistance in the axial direction (parallel to rod movement) while maintaining lower stiffness in radial and circumferential directions, thereby reducing friction during rod sliding.
Solution Approach 2:
The patent uses composite materials by incorporating fibers into the elastic body matrix. This composite structure combines the wear resistance and strength of fibers with the elasticity and friction-reducing properties of the elastic body, achieving both improved wear resistance and controlled friction characteristics.
2Reliability
If the elastic body having high hardness is used to enhance wear resistance, then the tightness of the lip portions against the rod is increased, but the smooth movement of the rod is interfered due to increased friction
Solution Approach 1:
The patent applies local quality by orienting fibers specifically in the axial direction within the elastic body of the lip portions. This creates anisotropic properties where the material has high stiffness and wear resistance in the axial direction (parallel to rod movement) while maintaining lower stiffness in radial and circumferential directions, thereby reducing friction during rod sliding.
Solution Approach 2:
The patent changes the material parameters by controlling fiber orientation and distribution within the elastic body. By adjusting the fiber orientation angle and density, the patent optimizes the balance between wear resistance (requiring higher stiffness) and smooth movement (requiring lower friction), achieving both goals simultaneously.
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 configuration improves wear resistance and maintains smooth rod movement by stabilizing the oil film and reducing friction, thus enhancing the durability of the shock absorber while minimizing the impact of friction on damping characteristics.
Implementation Method 1
the lip portion is formed of an elastic body containing fibers oriented in the axial direction
Implementation Method 2
increase axial modulus of elasticity and hardness while maintaining low radial and circumferential modulus
Implementation Method 3
the lip portion being brought into sliding contact with an outer circumference of the rod
Implementation Method 4
stabilizing the oil film and reducing friction
Data Source
AI summary
A seal member includes a base portion held by a cylinder, the base portion being configured such that a rod is inserted through the base portion, and a lip portion provided on the base portion, the lip portion being brought into sliding contact with an outer circumference of the rod, wherein the lip portion is formed of an elastic body containing fibers oriented in the axial direction of the rod.