Bicycle Sprocket Assembly with Multi-Radius Contact Points
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Solution Overview
Problem
Conventional bicycle rear wheel sprocket assemblies are heavy due to the use of strong, heavy materials like steel or titanium for sprockets, which increases the weight of the assembly and compromises on mechanical strength and lightness.
Innovation Solution
A set of sprockets comprising a first sprocket with a larger diameter, a second sprocket with a smaller diameter, and spacer elements arranged between them, with engagement portions for a freewheel body, where the sprockets rest at multiple contact points at different radial distances, distributing stress and enhancing structural rigidity, allowing for a lighter and stronger assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sprockets are made from strong materials like steel or titanium to withstand wear and loads, then the mechanical strength is improved, but the weight of the sprocket assembly increases
Solution Approach 1:
The sprocket assembly is divided into multiple sprockets of different diameters mounted on a common freewheel body. Each sprocket is independently supported by spacer elements, allowing the system to distribute loads across multiple components rather than requiring a single heavy structure to support all functions
Solution Approach 2:
The patent introduces multiple contact points at different radial distances from the rotation axis. This multi-dimensional contact arrangement (at different radii) distributes the torque transmission across various radial positions, reducing the stress concentration on any single point and allowing for lighter material usage while maintaining strength
2Adaptability or versatility
If multiple sprockets are mounted on the freewheel body, then the versatility of the transmission system is improved, but the complexity of the assembly increases
Solution Approach 1:
The spacer elements serve multiple functions simultaneously: they support the sprockets axially, provide radial positioning through engagement portions, and enable the mounting of multiple sprockets on a single freewheel body. This multi-functionality reduces the need for separate components for each function, simplifying the overall assembly
Solution Approach 2:
The spacer elements are pre-configured with engagement portions that mate with the freewheel body grooves before the sprockets are installed. This preliminary preparation of the mounting structure simplifies the assembly process and reduces the complexity of installing multiple sprockets
Data Source
AI summary
A set of sprockets has a first sprocket with a greater diameter, at least one second sprocket with a smaller diameter and one or more spacer elements operatively arranged between, and in abutment with the sprockets. At least one of the aforementioned sprockets and spacer elements has engagement portions with a freewheel body of a hub of a bicycle rear wheel, the engagement portions defining an ideal circumference for coupling with the freewheel body. The first sprocket rests against the second sprocket, through at least one of the one or more spacer elements, at at least one first contact point arranged at a first radial distance with respect to a longitudinal rotation axis, and at least one second contact point arranged at a second radial distance from the longitudinal rotation axis. The radial distance between the first contact point and the second contact point is at least equal to ⅓ of the radial extension between the circumference and a radially outer end of the second sprocket.