Six-Bar Rear Suspension for Pedaling and Shock Decoupling
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Solution Overview
Problem
Existing bicycle rear suspension systems fail to effectively decouple pedaling performance variables from shock performance variables, leading to unwanted loss of pedaling energy and inefficient shock absorption, particularly in four-bar linkage systems.
Innovation Solution
A six-bar linkage system is introduced, featuring two ternary links separated by binary links, allowing for independent tuning of pedaling and shock performance variables, with a shock absorber integrated into the linkage to control compression and movement of the rear wheel relative to the front triangle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a four-bar linkage system is used for rear suspension, then the structure is simpler, but pedaling performance variables cannot be independently tuned from shock performance variables
Solution Approach 1:
The patent divides the suspension system into separate functional segments by using a six-bar linkage with two independent ternary links. This segmentation allows one ternary link to control pedaling performance variables while the other controls shock performance variables, enabling independent tuning of each function without the coupling present in four-bar systems.
Solution Approach 2:
The patent transitions from a four-bar linkage (two-dimensional control) to a six-bar linkage with two ternary links (adding a third dimension of control). This dimensional expansion provides additional degrees of freedom, allowing independent adjustment of pedaling and shock characteristics that were previously coupled in the lower-dimensional four-bar system.
2Object-affected harmful factors
If shock absorption is increased for rough terrain, then rider comfort improves, but pedaling energy is unnecessarily absorbed and lost
Solution Approach 1:
The patent implements dynamic response characteristics through the six-bar linkage geometry, where the leverage ratios and linkage configurations change throughout the suspension travel. This allows the system to be soft and compliant when absorbing terrain bumps (reducing harmful effects) while maintaining stiffness and efficiency during pedaling power transfer (minimizing energy loss).
Solution Approach 2:
The patent applies different mechanical characteristics to different parts of the suspension system through the two separate ternary links. One linkage configuration optimizes for shock absorption quality when encountering terrain irregularities, while the other maintains pedaling efficiency quality, allowing each function to have its own optimized characteristics without compromising the other.
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 six-bar linkage system provides improved pedaling performance by maintaining high chain growth rates while achieving linear shock rate changes, enabling independent adjustment of geometry and shock tuning without affecting pedaling characteristics.
Implementation Method 1
a shock absorber integrated into the linkage to control compression and movement of the rear wheel relative to the front triangle
Data Source
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AI summary
A bicycle may include a front triangle and a rear suspension system that couples the front triangle to a rear wheel and is dampened by at least one shock absorber. The rear suspension system includes a six-bar linkage having two ternary links separated from each other by one or more binary links, such that the two ternary links do not share a common joint. One of the ternary links may comprise a chain stay. In some examples, the other ternary link may comprise the front triangle. In some examples, the other ternary link may comprise a rocker arm coupling a seat stay link to the shock absorber.