Dual-Chamber Bicycle Air Spring for Bottom-Out Resistance
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Solution Overview
Problem
Conventional bicycle air springs have a non-ideal load displacement curve and experience spikes due to the adiabatic effect, compromising performance in mountain bike suspension systems, particularly in terms of bump absorption and pedaling efficiency.
Innovation Solution
An improved air spring design featuring a first and second chamber with a flow passage and a seal that restricts flow between the chambers at specific compression levels, allowing independent tuning of spring curves to control end-of-stroke forces and maintain optimal bump absorption performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a conventional air spring is used in mountain bike suspension, then the suspension system is lightweight, but the load-displacement curve is non-ideal and experiences spikes due to the adiabatic effect
Solution Approach 1:
The air spring is divided into two separate chambers (first chamber and second chamber) that can be independently controlled. This segmentation allows the suspension to have different spring rates in different compression zones, eliminating the non-ideal spikes in the load-displacement curve while maintaining the lightweight advantage of air springs.
Solution Approach 2:
The patent implements a dynamic flow control mechanism where a flow passage allows air to move between chambers during compression, and a seal selectively restricts this flow at specific compression levels. This dynamic adjustment enables the suspension to adapt its characteristics throughout the compression stroke, providing smooth progression without adiabatic spikes.
2Stability of the object's composition
If the air spring allows free flow between chambers, then the spring curve is smooth, but the end-of-stroke forces are excessive causing bottoming out
Solution Approach 1:
The seal is positioned to restrict flow between chambers at a predetermined compression level (e.g., 75-90% of total travel). This preliminary sealing action prevents excessive force buildup at the end of stroke by controlling when the second chamber becomes isolated, thereby preventing bottoming out while maintaining smooth spring curve characteristics throughout the majority of the compression stroke.
3Force
If the seal restricts flow between chambers early in compression, then bottoming out is prevented, but bump absorption performance deteriorates
Solution Approach 1:
The patent optimizes the seal positioning parameter to restrict flow at a specific compression threshold (e.g., 75%, 80%, 85%, 90%, 95%, or 97% of total travel). By carefully selecting this parameter, the system maintains smooth spring characteristics and bump absorption performance during the majority of the compression stroke, while only restricting flow when approaching full compression to prevent bottoming out.
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 improved air spring provides enhanced resistance to bottoming out and maintains consistent performance across various terrain conditions, ensuring improved pedaling efficiency and ride comfort by independently scaling spring force in response to rider weight and terrain demands.
Implementation Method 1
a first piston and a first body cooperating to define a pressurized first chamber including a gas... a pressurized second chamber... the pressurized first chamber and pressurized second chamber exert expansion force on the air spring
Implementation Method 2
The air spring has a seal to selectively permit, prevent, and/or restrict flow between the first chamber and the second chamber
Implementation Method 3
a conventional air spring may experience spikes in the load v. displacement curve when the air spring experiences high velocities due to the adiabatic effect
Data Source
AI summary
An air spring includes a first body; a first piston cooperating with the first body to define a pressurized first chamber including a gas, the first piston configured to slideably move relative to the first body; a pressurized second chamber; a flow passage between the first chamber and the second chamber; and a seal to selectively permit or restrict flow between the first chamber and the second chamber depending on a position of the first piston with respect to the first body.