Variable-Diameter Sprocket for Seamless Bicycle Gear Ratio Control
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Solution Overview
Problem
Traditional bicycle transmission systems lack the ability to provide an infinitely variable gear ratio without jarring effects, as they rely on derailleurs that can cause discomfort and safety issues due to mechanical limitations and high maintenance requirements.
Innovation Solution
A gear set with variably adjusting radius, either mechanically or electronically, that allows for continuous adjustment of gear ratios by expanding or contracting the sprocket diameter, eliminating the need for derailleurs and enabling seamless transitions during pedaling, using sensors and energy storage systems to optimize gear settings based on terrain and rider input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional derailleur system is used to change gear ratios, then gear ratio adjustment is possible, but it causes jarring effects and mechanical limitations that reduce rider comfort and safety
Solution Approach 1:
The sprocket diameter is made dynamically adjustable during operation. The variable diameter sprocket allows continuous change of the effective radius while the chain is engaged, enabling smooth gear ratio transitions without the jarring effects of traditional derailleur systems. This dynamic adjustment capability resolves the contradiction by providing both gear ratio adaptability and rider comfort through uninterrupted power transmission.
Solution Approach 2:
The invention changes the physical parameter of the sprocket diameter to achieve variable gear ratios. By adjusting the effective radius of the sprocket while maintaining chain engagement, the system provides continuous gear ratio adjustment without disengagement or shifting mechanisms, thereby eliminating the harmful jarring effects and improving rider comfort and safety.
2Adaptability or versatility
If a derailleur system is used for gear ratio changes, then multiple gear ratios are achievable, but maintenance requirements increase due to mechanical complexity
Solution Approach 1:
The invention extracts and eliminates the derailleur mechanism from the transmission system. By using a variable diameter sprocket that adjusts its effective radius directly, the system removes the complex shifting mechanisms, cables, and pulleys associated with derailleurs, thereby reducing maintenance requirements while maintaining gear ratio variability.
Solution Approach 2:
The variable diameter sprocket serves multiple functions: it provides gear ratio adjustment, maintains continuous chain engagement, and eliminates the need for separate shifting mechanisms. This multi-functionality reduces the overall mechanical complexity and maintenance requirements compared to traditional derailleur systems.
3Adaptability or versatility
If the sprocket diameter is made variable to enable continuous gear ratio adjustment, then gear ratio adaptability improves, but device complexity increases
Solution Approach 1:
The variable diameter sprocket is divided into multiple segments or adjustable radius sections that can be positioned at different radial distances from the center. This segmentation allows the sprocket to provide multiple effective radii for gear ratio adjustment while keeping each individual segment relatively simple in design, thereby managing overall device complexity.
Data Source
AI summary
A gear system based on variably expandable gears, where input from either or both an operator or a computer processor may induce selective radial expansion and contraction of at least one gear in a gear set. The computer processor may be programmed to establish and maintain a desired gear ratio, regardless of the various variable forces which may be encountered, permitting gear setting and adjustment to control a desired parameter, such as speed, revolutions-per-minute, and watts with minimal effort by the operator.