Bicycle Damping Strut with Time-Adaptive Bias Regulator
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Solution Overview
Problem
Damping struts in bicycle wheel suspensions face challenges in providing consistent and adaptive damping forces to ensure safety and comfort, particularly during diverse riding situations such as encountering obstacles or abrupt braking, where current systems fail to effectively attenuate unwanted movements and maintain optimal tire-road contact.
Innovation Solution
A damping strut with a hydraulic shock absorber equipped with a retract detection device, compression stage throttle, and bias regulator, which adjusts the damping force by increasing the bias value during retraction and resetting it during extension, allowing for dynamic generation of damping forces that vary with retraction duration but remain independent of stroke velocity, mimicking an active spring system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the damping strut uses a conventional hydraulic shock absorber with fixed damping characteristics, then the structure is simple and reliable, but the damping force cannot adapt to different riding situations (obstacles vs. undesired movements)
Solution Approach 1:
The patent implements dynamic damping by making the damping force variable rather than fixed. The bias regulator dynamically adjusts the bias value of the biasing means based on retraction duration detected by the retract detection device, allowing the compression stage throttle to provide different damping forces for different riding situations. This transforms a static damping system into a dynamic one that adapts to changing conditions.
Solution Approach 2:
The patent employs feedback control through the retract detection device that monitors retraction duration and feeds this information to the bias regulator. The bias regulator then adjusts the bias value accordingly, creating a closed-loop control system. This feedback mechanism enables the damping strut to distinguish between desired retraction (obstacle clearance) and undesired retraction (braking/pedaling movements) and respond appropriately.
2Speed
If the damping strut generates high damping force immediately upon retraction, then undesired movements are attenuated quickly, but the wheel cannot dodge obstacles smoothly and tire contact is lost
Solution Approach 1:
The patent uses preliminary action by having the retract detection device start timing immediately when retraction begins, allowing the bias regulator to progressively increase the bias value during the retraction event. This gradual buildup of damping force rather than immediate maximum force allows the wheel to smoothly clear obstacles while still providing eventual resistance to undesired movements.
Solution Approach 2:
The patent implements periodic action through the time-based adjustment of damping force. The bias value increases during a first time period after retraction starts, then remains constant during a second time period. This temporal variation in damping force creates different damping characteristics for different phases of the retraction event, enabling smooth obstacle clearance followed by firm attenuation of undesired movements.
3Stability of the object's composition
If the damping strut uses velocity-independent damping force, then the damping characteristic is consistent regardless of stroke speed, but the system cannot differentiate between fast obstacle clearance and slow undesired movements
Solution Approach 1:
The patent introduces time duration as an intermediary parameter between the physical motion and the damping force. Instead of directly using velocity to control damping, the retract detection device measures retraction duration, and the bias regulator uses this temporal information to adjust the bias value. This intermediary approach allows the system to maintain velocity-independent damping while still differentiating between different types of movements based on their duration characteristics.
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 solution ensures high damping forces are generated at obstacle maxima, effectively decelerating the wheel and preventing further retraction, while also rapidly increasing resistance during undesired movements like braking or pedaling-induced rocking, enhancing safety and comfort by maintaining optimal tire contact and reducing wheel load fluctuations.
Implementation Method 1
the damping fluid flows through the compression stage throttle in a direction opposite to a closing direction of the disk valve as the hydraulic shock absorber is retracted thereby generating a damping strut resistance force
Implementation Method 2
The compression stage throttle has a biasing means for biasing the valve disk against a through flow direction of the disk valve
Data Source
AI summary
A damping strut with a hydraulic shock absorber has a damping volume filled with an incompressible damping fluid, a retract detection device, and a compression stage throttle having a disk valve with a valve disk. The damping fluid flows through the compression stage throttle during a retraction of the shock absorber and generates a damping strut resistance force. A biasing means for biasing the valve disk against a through flow direction of the disk valve has a force-distance-characteristic curve in a range of the valve stroke of the valve disk, a first derivative of which is substantially zero and has a value (K). A bias regulator couples the biasing means with the valve disk and is interconnected with the retract detection device. When the retraction of the shock absorber starts, the value (K) is raised during a first period of time starting at a single start value.