Bicycle Frame Pivot Kinematics for Fatigue Reduction
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Solution Overview
Problem
Bicycle frames experience deformation and reduced lifespan due to the integration of shock absorbers, which increases fatigue during shock absorption on rugged road surfaces.
Innovation Solution
A bicycle frame design incorporating a front frame, rear frame, upper linkage, and shock absorber with specific pivot axes configurations to manage compression ratios and minimize deformation, particularly by setting the distance variation between pivot locations to reach a maximum value within a controlled compression range (0% to 60%) to reduce frame fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shock absorber is integrated with the frame to provide buffering on rugged road surfaces, then shock absorption capability is improved, but frame deformation and fatigue increase during the shock absorbing process
Solution Approach 1:
The frame is divided into front frame and rear frame components connected by pivots, allowing independent movement and stress distribution. The upper linkage connects these segments with additional pivots, enabling the frame to segment the shock absorption forces across multiple joints rather than concentrating stress on a single integrated structure.
Solution Approach 2:
The patent specifies precise geometric parameters for pivot positions and distances. The distance between the main pivot axis and the second pivot axis is controlled within 2-4mm, and the distance between the first and second pivot axes on the upper linkage is controlled within 2-4mm. These parameter constraints optimize the kinematic chain to minimize frame deformation while maintaining shock absorption effectiveness.
2Adaptability or versatility
If multiple pivots are designed on the frame to integrate the shock absorber, then shock absorption function is achieved, but frame deformation occurs during the shock absorbing process
Solution Approach 1:
The frame employs a dynamic linkage system where the upper linkage can rotate and adjust its configuration through pivots at the first and second pivot axes. This dynamic adaptation allows the linkage to optimize its geometry during shock absorption, maintaining favorable kinematic conditions that reduce frame deformation while preserving the shock absorption function.
Solution Approach 2:
The patent controls the geometric parameters of the pivot system, specifically maintaining the distance between pivot axes within 2-4mm ranges. This parameter optimization ensures that the kinematic chain operates in a favorable configuration that minimizes deformation of the frame during shock absorption events.
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 design enhances the frame's lifespan by managing deformation and stress distribution, preventing excessive damage from high compression forces and maintaining structural integrity over time.
Implementation Method 1
a frame for a bicycle having a shock-absorbing function
Implementation Method 2
When the compression ratio of the shock absorber is in a range between 0% and 60%, the distance variation between a pivot location of the rear frame at the second pivot axis and a pivot location of the rear frame at the main pivot axis reaches a maximum value thereof
Implementation Method 3
The upper linkage is pivoted to the front frame at a first pivot axis and is pivoted to the rear frame at a second pivot axis
Data Source
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AI summary
A frame for a bicycle includes a front frame, a rear frame, an upper linkage, and a shock absorber. The rear frame is pivoted to the front frame at a main pivot axis. The upper linkage is pivoted to the front frame at a first pivot axis and is pivoted to the rear frame at a second pivot axis. The shock absorber is pivoted to the upper linkage at a third pivot axis and is pivoted to the front frame. When a compression ratio of the shock absorber is in a range between 0% and 60%, a distance variation between a pivot location of the rear frame at the second pivot axis and a pivot location of the rear frame at the main pivot axis reaches a maximum value thereof.