Bicycle Cassette Layout With an 8-10 Tooth Cog for Wider Gear Range
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Solution Overview
Problem
Conventional bicycle rear cassettes are limited by a minimum cog tooth count of 11, restricting the tooth ratio and requiring replacement of chainrings for different gear ratios, leading to higher expenses and unstable connections due to separation rings occupying connection areas.
Innovation Solution
An additional cog with 8-10 teeth is mounted opposite the rear hub, increasing the tooth ratio and maintaining compatibility with existing chainrings, with a threaded ring and cap design to enhance connection stability and smooth gear shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the minimum cog tooth count is maintained at 11, then the driver body diameter can be minimized, but the tooth ratio is restricted and chainring replacement is required for different gear ratios
Solution Approach 1:
The patent adds a new dimension to the cassette structure by mounting an additional small cog (8-10 teeth) on the opposite side of the driver body from the main cogs. This allows the system to achieve a wider tooth ratio range without increasing the minimum diameter of the driver body, as the additional cog utilizes the available space in the opposite direction.
2Stability of the object's composition
If separation rings are used between cogs, then the cogs are evenly spaced, but the connection area is occupied leading to unstable connections
Solution Approach 1:
The patent removes the separation ring component from between the cogs and instead integrates the spacing function directly into the driver body structure. The driver body includes built-in spacing features that maintain proper cog separation while preserving the full connection area between cogs and the driver body, thereby eliminating the connection instability caused by separation rings.
3Adaptability or versatility
If chainrings are replaced to change gear ratios, then the tooth ratio can be adjusted, but the expenses increase due to BCD compatibility requirements
Solution Approach 1:
The patent creates a dynamically adjustable gear system by adding a removable additional cog that can be mounted or removed based on desired gear ratios. This allows users to adjust the tooth ratio by simply adding or removing the small cog without replacing entire chainring assemblies, significantly reducing costs while maintaining BCD compatibility with existing cranksets.
4Adaptability or versatility
If an additional small cog is added to increase tooth ratio, then the gear range is expanded, but the space availability on the driver body is constrained
Solution Approach 1:
The patent utilizes the opposite side of the driver body as a new spatial dimension for mounting the additional small cog. This approach effectively doubles the available mounting space on the driver body, allowing the addition of the small cog without encroaching on the space required by the main cogs, thus expanding the tooth ratio range while maintaining compact overall dimensions.
Data Source
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AI summary
A bicycle cassette with increased tooth ratio includes a driver body (10) connected to a bicycle rear hub, and multiple cogs (13-18, 20) which are sequentially mounted to the driver body with equal spacing. An additional cog (40) is mounted to the driver body and located opposite to the rear hub. The additional cog has 8-10 teeth. The tooth ratio is increased by the additional cog and the chainring to break through the limitation of tooth ratio of existing bicycle cassettes, and to increase the number of the gears of the bicycle cassette.