Dual-Sided Cycle Wheel Suspension for Low-Stiction Front Stability
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Solution Overview
Problem
Telescopic front suspension forks for two-wheeled vehicles face issues such as high stiction, reduced mechanical trail during suspension compression, limited leverage ratio, increased angle of attack stability and stiction, and front suspension dive, which affect handling and stability, especially under braking conditions.
Innovation Solution
A wheel suspension assembly with a steering fork featuring a first and second arm, a shock link, a shock absorber with an inline configuration, a gas spring unit, and a control link, arranged in a trailing configuration to maintain clearance for the front wheel during compression and extension, allowing for increased mechanical trail and leverage ratio, reducing stiction, and improving stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If telescopic fork stantions are made larger to support fore/aft loads, then structural strength is improved, but stiction increases and stability deteriorates
Solution Approach 1:
The suspension system is divided into separate functional components: a telescopic fork for fore/aft load support and a linkage system (control links, brake links, drag links) for bump absorption. This segmentation allows each component to be optimized independently, reducing overall stiction while maintaining structural strength.
Solution Approach 2:
Linkage members (control links, brake links, drag links) are introduced as intermediaries between the wheel assembly and the fork stantions. These linkages transmit forces while allowing the fork stantions to remain smaller, thereby reducing stiction and improving stability during braking and cornering.
2Loss of energy
If suspension compression is increased to improve bump absorption, then shock absorption is improved, but mechanical trail reduces and stability deteriorates
Solution Approach 1:
The linkage system is designed with dynamic geometry where the effective mechanical trail changes with suspension compression. As the suspension compresses, the linkage angles adjust to maintain or increase mechanical trail, thereby preserving stability during bump absorption events.
Solution Approach 2:
The system changes the geometric parameters of the linkage arrangement during suspension compression. By adjusting the effective trail parameter dynamically through linkage geometry changes, the system maintains stability while allowing sufficient compression for bump absorption.
3Reliability
If fork stantion angle is made slacker to improve angle of attack stability, then angle of attack stability is improved, but bushing load increases and stiction increases
Solution Approach 1:
The suspension system separates the functions of angle management and bump absorption. The telescopic fork handles fore/aft loads with a steeper angle, while the linkage system manages angle of attack stability, allowing the fork stantions to operate at optimal angles with reduced bushing load and stiction.
Solution Approach 2:
Control links and brake links serve as intermediaries that manage the angle of attack independently of the fork stantion angle. This allows the fork stantions to maintain a steeper, lower-stiction angle while the linkage system provides the necessary angle of attack stability.
4Loss of energy
If leverage ratio is increased to improve shock absorption efficiency, then shock absorption is improved, but device complexity increases
Solution Approach 1:
The linkage system provides a dynamic leverage ratio that varies with suspension compression, optimizing shock absorption efficiency across the full range of motion. The changing geometry of the linkage members creates a progressive leverage effect without requiring complex mechanical advantage mechanisms.
Solution Approach 2:
The system uses spatial arrangement and angular relationships in the linkage geometry to achieve leverage multiplication. By utilizing the third dimension (angular orientation of links) rather than simple linear mechanical advantage, the system achieves high leverage ratios with relatively simple components.
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 solution enhances stability and reduces stiction during braking and cornering, providing better shock absorption and handling characteristics compared to traditional telescopic fork systems.
Implementation Method 1
a spring unit (48) having a gas spring (188), a first spring mount (57), and a second spring mount (59)
Implementation Method 2
a shock absorber (44) having an inline configuration, a damper (94), an inshaft (80), and an outshaft (90)
Data Source
AI summary
A trailing link multi-bar suspension assembly for a cycle having improved stability includes a first arm having a first side and a second side, a first arm fixed pivot and a first arm shock pivot, the first side and second side defining a wheel opening. A shock link has a shock link fixed pivot and a shock link floating pivot. A shock absorber has an inline configuration, a gas spring, a first shock mount, and a second shock mount, and the shock absorber is substantially located on the first side or second side of the wheel opening. A spring unit, has a gas spring comprising a spring body, a first spring mount and a second spring mount, and the spring unit is substantially located on the first side or second side of the wheel opening A wheel carrier has a wheel carrier first pivot and a wheel carrier second pivot spaced apart from one another, and a wheel mount that is adapted to be connected to a wheel. A control link has a control link floating pivot and a control link fixed pivot, the control link floating pivot being pivotably connected to the wheel carrier second pivot, and the control link fixed pivot being pivotably connected to the first arm control pivot.