Bicycle Belt Drive Cog Debris Venting Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Belt-driven bicycle power train systems are less tolerant of debris compared to chain-driven systems, as debris can become trapped between the belt and cog, leading to inefficient interaction and potential derailing, necessitating a solution to vent debris without interfering with cog operation.
Innovation Solution
A debris venting cog design with an outer circumferential surface and cavities shaped to interact with the belt, featuring vents that direct debris radially inward and laterally to maintain efficient interaction between the belt and cog, preventing derailing and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a belt-driven power train system is used, then quieter operation and smoother power transmission are achieved, but the system becomes less tolerant of debris and more prone to derailing
Solution Approach 1:
The patent extracts the harmful debris from the interaction zone between the belt and cog by providing dedicated debris ejection features. The cog design includes channels and surfaces that actively remove debris from the cavity where the belt tooth engages, preventing debris from interfering with the driving interaction and causing derailment.
Solution Approach 2:
The patent converts the potentially harmful debris into a beneficial ejection mechanism. The interaction between the belt tooth and cog cavity, which could trap debris, is designed to actively propel debris outward through specific ejection channels. The normal operational forces are harnessed to eject debris rather than trap it, transforming a harmful effect into a self-cleaning mechanism.
2Strength
If the cog cavity is sealed to protect internal components, then component protection is improved, but debris accumulation occurs leading to inefficient interaction
Solution Approach 1:
The cog design implements local quality by having different regions of the cog serve different functions. The cavity structure provides protection in most areas while incorporating specific localized ejection channels and vent features in strategic locations. This allows the cog to maintain component protection while enabling controlled debris ejection paths that preserve power transmission efficiency.
Solution Approach 2:
The patent introduces intermediary ejection channels and vent features as mediators between the sealed cavity and the external environment. These intermediary structures allow debris to be actively removed from the cavity without compromising the overall protective sealing of the cog components, maintaining both component protection and operational efficiency.
3Object-affected harmful factors
If debris ejection features are added to the cog, then debris removal is improved, but the cog structure becomes more complex
Solution Approach 1:
The patent merges the debris ejection function with the existing cog structural elements. The ejection channels are integrated into the cog body and cavity structure rather than being separate components. The drive walls and web walls of the cog are configured to serve both structural support functions and debris ejection pathways, combining multiple functions into a unified structure that reduces overall complexity.
Solution Approach 2:
The cog design implements multi-functionality where the same structural elements serve multiple purposes. The cavity walls and web walls provide both structural support for the cog and serve as debris ejection channels. The vent features simultaneously protect internal components while enabling debris removal. This multi-functionality reduces the need for additional separate components, maintaining structural simplicity while achieving effective debris ejection.
Data Source
AI summary
A debris venting cog particularly useful for belt driven bicycle power train systems. The cog includes an outer circumferential surface that is shaped to drivingly interact with a flexible drive member such as a belt. The cog includes a number of cavities that are each shaped to interact with a tooth of the belt. A vent fluidly connects at least one cavity to atmosphere and is shaped to direct debris that can accumulate in the cavity or the belt in a radially inward and lateral direction so as to maintain a desired driving interaction between the belt and the cog.