Front Fork Seal Arrangement for Air Spring Dust Protection
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Solution Overview
Problem
Conventional front fork spring legs with air springs suffer from seal impairment due to abrasive dust from the piston ring, leading to leakage and reduced suspension performance.
Innovation Solution
The arrangement of inward-facing and outward-facing seal members on the guide rod, with lips oriented to prevent abrasive dust from reaching the seals, ensures stable air spring characteristics by preventing seal scratches and maintaining air pressure integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a piston ring is provided on the guide rod to seal the air spring chamber, then air pressure leakage is prevented, but abrasive dust is generated that scratches the seal members and impairs sealing performance
Solution Approach 1:
An outward-facing seal member is introduced as an intermediary component between the piston ring and the inward-facing seal member. This intermediate seal member blocks abrasive dust generated by the piston ring from reaching and scratching the inward-facing seal member, while still allowing the piston ring to perform its sealing function. The outward-facing seal member acts as a protective barrier that filters out harmful particles.
Solution Approach 2:
The sealing system is divided into multiple independent seal members with different orientations: an inward-facing seal member for preventing air leakage, a piston ring for primary sealing, and an outward-facing seal member for blocking abrasive dust. Each component performs a specific sealing function, and their combined arrangement solves the contradiction between maintaining air pressure and preventing dust contamination.
2Reliability
If seal members are provided to maintain air pressure in the inner air spring chamber, then suspension function is maintained, but lubricating oil may enter the chamber and increase air pressure to critical levels
Solution Approach 1:
The seal members are designed with asymmetric orientations: the inward-facing seal member has its lip oriented toward the inner air spring chamber to prevent air leakage, while the outward-facing seal member has its lip oriented away from the chamber to prevent lubricating oil from entering. This asymmetric configuration allows each seal member to selectively block different substances based on its orientation.
Solution Approach 2:
The outward-facing seal member serves as an intermediary barrier that prevents lubricating oil from the lower part of the guide cylinder from entering the inner air spring chamber. It acts as a protective interface between the oil-containing environment and the air spring chamber, allowing the suspension system to maintain proper air pressure without oil contamination.
3Reliability
If the inward-facing seal member lip is oriented toward the inner air spring chamber to prevent air leakage, then air pressure is maintained, but abrasive dust can scratch the seal member and impair sealability
Solution Approach 1:
The outward-facing seal member is positioned as an intermediary component that blocks abrasive dust from reaching the inward-facing seal member. This intermediate barrier protects the precision surface of the inward-facing seal member from dust contamination, maintaining both air pressure integrity and seal member integrity simultaneously.
Solution Approach 2:
The outward-facing seal member provides beforehand protection by blocking abrasive dust before it can reach and damage the inward-facing seal member. This preventive arrangement ensures that the inward-facing seal member maintains its sealing integrity throughout the operational life of the air spring.
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 effectively prevents seal impairment, maintaining the spring force and suspension function by blocking abrasive dust and preventing lubricating oil from entering the air spring chamber, thus ensuring stable air spring characteristics.
Implementation Method 1
a piston ring and a seal member are provided on an outer periphery of the guide of the guide rod so as to be slidably in contact with an inner periphery of the guide cylinder
Implementation Method 2
this piston ring produces abrasive dust
Implementation Method 3
The inward-facing seal member has a lip that is slidably in contact with the inner periphery of the guide cylinder and is oriented toward the inner air spring chamber
Implementation Method 4
The outward-facing seal member prevents a lubricating oil located in a lower part of the guide cylinder from entering the inner air spring chamber
Implementation Method 5
an inner air spring chamber defined by the guide of the guide rod is formed in the inside of the guide cylinder
Implementation Method 6
to maintain a spring force of the air spring in the inner air spring chamber
Data Source
Figure 1
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Figure 3
AI summary
Provided is a front fork spring leg capable of stably maintaining air spring characteristics. The front fork spring leg has an inward-facing seal member (51), an outward-facing seal member (66), and a piston ring (24) arranged on an outer periphery of a guide (23) of a guide rod (22) sequentially in this order along an axial direction of the guide from the side close to an inner air spring chamber (50) toward the side far from the same. The inward-facing seal member (51) has a lip which is slidably in contact with the inner periphery of the guide cylinder (21), with this lip being oriented toward the inner air spring chamber (50) while the outward-facing seal member (66) has a lip which is slidably in contact with the inner periphery of the guide cylinder (21), with this lip being oriented in the opposite direction to the inner air spring chamber (50).