Roller Chain Sprocket Tooth Profile for Lower Friction Wear

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Solution Overview

Problem

Existing power transmission systems with drive sprockets and members, such as roller chains, suffer from inefficiencies due to significant loads causing relative movement and friction, leading to energy losses and component wear.

Innovation Solution

A transmission system with a drive sprocket and roller chain where each tooth has distinct engagement surfaces and articulation angles, optimizing contact points to reduce friction and wear by increasing the articulation angle associated with more efficient pin articulations and decreasing that of less efficient bush articulations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional drive sprockets and roller chains are used with significant loads, then power transmission capability is maintained, but relative movement and friction occur leading to energy losses and component wear

Engineering Contradiction:

Improveenergy lossesVSAvoidcomponent wear

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The tooth profile is designed with different engagement surfaces having distinct geometric properties. The first engagement surface has a first profile curvature while the second engagement surface has a second profile curvature, creating locally optimized contact conditions for reducing friction and wear at each contact point

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The tooth profile is asymmetric with the first side having different curvature characteristics than the second side. This asymmetry allows optimization of the articulation angle at each contact location, creating more efficient pin articulations and less efficient bush articulations to minimize overall energy loss and wear

Inventive Principle:

Principle #4Asymmetry

2Power

If chain links articulate at connecting pivots under high loads, then power transmission is maintained, but friction leads to energy losses and component wear

Engineering Contradiction:

Improvepower transmissionVSAvoidfriction energy losses

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The articulation angle parameter is optimized by designing specific tooth profile curvatures. The first and second profile curvatures are selected to achieve optimal articulation angles that minimize frictional energy losses during chain link articulation while maintaining power transmission capability

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional tooth profiles are used, then manufacturing simplicity is maintained, but articulation angles cannot be optimized leading to increased wear and energy losses

Engineering Contradiction:

Improvetooth profile manufacturingVSAvoiddrive lifetime

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The tooth profile incorporates locally optimized curvature characteristics on different sides of the tooth. These localized geometric features are designed to optimize articulation angles for reduced wear and energy loss, while remaining manufacturable using conventional machining processes

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11732782B2Transmission system

Publication Date: 2023.08.22 NEW MOTION LABS LTD

AI summary

A transmission system can include a drive sprocket and a drive member adapted to mesh with the drive sprocket. The drive sprocket can include a plurality of teeth for meshing with the drive member to transmit rotary motion, and the drive member can include a plurality of engagement pockets adapted to engage the teeth of the drive sprocket.