Multi-Layered Bicycle Sprocket Axial Stacking Weight Reduction
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Solution Overview
Problem
Bicycle sprockets face challenges in increasing the number of gears without altering the conventional bicycle frame dimensions, as the rear end of the frame has limited space for mounting the wheel and sprocket assembly, and existing solutions do not effectively balance weight reduction with maintaining necessary rigidity.
Innovation Solution
A bicycle sprocket with a multi-layered structure comprising a sprocket body and layered members, where at least one of the layered members has concavo-convex portions, and the members are attached using methods like diffusion bonding or integral molding to achieve weight savings and improved rigidity, with specific gravity differences between the layers optimizing weight distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of sprockets is increased to provide more gears, then the transmission versatility is improved, but the space required at the rear end of the bicycle frame increases
Solution Approach 1:
The patent transitions from a conventional single-layer sprocket design to a multi-layered sprocket structure, utilizing the axial dimension to stack multiple sprocket layers. This allows multiple gears to be arranged in the axial direction rather than requiring increased radial space, thereby increasing transmission versatility while maintaining compact rear end dimensions.
Solution Approach 2:
The patent implements nested sprocket layers where multiple sprocket wheels are positioned concentrically at different axial locations. The sprockets are arranged like nested dolls, with each layer fitting within the overall boundary of the sprocket assembly, maximizing gear count within limited space.
2Weight of moving object
If lightweight materials are used to reduce sprocket weight, then the weight is reduced, but the rigidity and strength decrease
Solution Approach 1:
The patent employs composite construction by combining multiple sprocket layers made of lightweight materials (such as aluminum or magnesium alloys) with a central hub structure. The multi-layer configuration distributes mechanical loads across multiple surfaces, compensating for the lower individual material strength and maintaining overall rigidity while achieving weight reduction.
Solution Approach 2:
The sprocket is divided into multiple discrete layers that can be independently designed and assembled. This segmentation allows optimization of each layer's thickness and material properties to balance weight and strength requirements, while the stacked configuration provides distributed load-bearing capacity.
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
The multi-layered sprocket design effectively reduces weight while maintaining rigidity, allowing for more gears without increasing frame dimensions, and ensures sufficient strength to resist bending and chain engagement.
Implementation Method 1
the members are attached using methods like diffusion bonding or integral molding
Data Source
AI summary
A bicycle sprocket includes a sprocket body and a plurality of sprocket teeth. The sprocket teeth extend radially outwardly from an outer periphery of the sprocket body. The sprocket body includes a first layered member, a second layered member and a third layered member. The first layered member has a first axial surface and a second axial surface. The second layered member is attached to the first axial surface such that the first and second layered members overlap each other in an axial direction as viewed parallel to a rotational axis. The third layered member is attached to the second axial surface such that the first and third layered members overlap each other in the axial direction as viewed parallel to the rotational axis. At least one of the second and third layered members has at least one concavo-convex portion.