Asymmetric Chain Ring Teeth for Stable Chain Retention

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Solution Overview

Problem

Conventional chain rings with uniform teeth lead to gaps that increase the risk of chain disengagement and weight, and alternating teeth designs may cause entanglement issues with debris, while attempting to match link widths.

Innovation Solution

A chain ring design with teeth of identical thickness, featuring alternating rectangular and non-rectangular cross-sectional shapes to fit within inner and outer links, applying lateral pressure in specific directions and offsetting top surfaces asymmetrically to improve interfitting with drive chains.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If alternating teeth of different sizes are used to match link widths, then chain interconnection is improved, but weight increases and risk of tooth catching increases

Engineering Contradiction:

Improvechain interconnectionVSAvoidchain ring weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies local quality by providing different tooth configurations at different locations around the chain ring. Specifically, first teeth are designed with a first configuration optimized for engaging inner links, while second teeth are designed with a second configuration optimized for engaging outer links. This allows each tooth to be locally optimized for its specific engagement requirement without requiring all teeth to be larger, thereby improving chain interconnection while controlling weight.

Inventive Principle:

Principle #3Local quality

2Reliability

If larger teeth are used to reduce gaps, then chain disengagement risk is reduced, but weight increases and debris entanglement increases

Engineering Contradiction:

Improvechain disengagement preventionVSAvoiddebris entanglement

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If uniform teeth are used, then manufacturing is simplified, but gaps between teeth and chain links increase

Engineering Contradiction:

Improvetooth manufacturingVSAvoidchain interconnection

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

4Adaptability or versatility

If alternating narrow and wide teeth are used, then link width matching is improved, but device complexity increases

Engineering Contradiction:

Improvelink width matchingVSAvoidtooth configuration complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11719325B2Chain ring with teeth oppositely laterally engaging a drive chain

Publication Date: 2023.08.08 EKO SPORT INC

AI summary

A drive system for a vehicle includes a chain ring and a drive chain. The chain ring has a plurality of teeth serially arranged and joined to one another. A first subset of teeth has a first outer face that applies a lateral pressure to a link of a drive chain in a first direction. A second subset of teeth has a second outer face that applies a lateral pressure to another link of a drive chain in a second direction. The teeth all have substantially the same width. The top surfaces of the teeth are offset from the centerline of the drive chain. The centerlines of the top surfaces of the teeth are arranged asymmetrically on one side of the centerline of the drive chain.