Chain Link Recess Geometry for Sprocket Engagement

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Solution Overview

Problem

Conventional transmission chains for variable speed drivetrains face difficulties in movement between sprockets due to insufficient space width, leading to challenges in forming and sprocket engagement, as well as issues with separation from forming dies.

Innovation Solution

The chain design includes inner and outer link units with recesses having parallel edges, increasing the engaging space width between chain plates, and using inclined guide surfaces to facilitate smooth sprocket engagement and easy die separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If arc-shaped edges are used in the recess of inner chain plates, then the engaging space width is increased to facilitate sprocket movement, but the separation from forming die becomes difficult

Engineering Contradiction:
Improveengaging space widthVSAvoidseparation from forming die
Core Design Contradiction:
Area of moving objectVSEase of manufacture

Solution Approach 1:

The recess edges are designed with arc-shaped contours that provide curved surfaces for sprocket tooth engagement, facilitating smooth movement between sprockets while maintaining manufacturability through proper die design

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The recess geometry is designed with asymmetric features where the arc-shaped edges are positioned and dimensioned to optimize both the engaging space width for sprocket passage and the separation characteristics from the forming die during manufacturing

Inventive Principle:
Principle #4Asymmetry

2Area of moving object

If inclined grooves are used in inner chain plates, then the engaging space width is increased, but the width remains insufficient for smooth sprocket movement

Engineering Contradiction:
Improveengaging space widthVSAvoidsprocket movement smoothness
Core Design Contradiction:
Area of moving objectVSEase of operation

Solution Approach 1:

Arc-shaped edges replace inclined grooves to provide curved engagement surfaces that better accommodate the rounded sprocket teeth, enabling smoother passage and reducing binding during variable speed operation

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The geometry of the recess is optimized by changing from linear inclined grooves to arc-shaped edges, adjusting the curvature radius and position parameters to achieve both sufficient width and smooth engagement characteristics

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If protrusions are added to outer chain plates, then collision with sprockets is reduced, but the engaging space width in inner link units remains small

Engineering Contradiction:
Improvecollision with sprocketsVSAvoidengaging space width
Core Design Contradiction:
Object-affected harmful factorsVSArea of moving object

Solution Approach 1:

The chain structure is divided into distinct functional elements where outer chain plate protrusions handle collision mitigation while inner chain plate recesses are independently optimized for engaging space width, allowing both requirements to be satisfied simultaneously

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the chain structure are given different geometric qualities - protrusions on outer plates for collision protection and arc-shaped recesses on inner plates for engagement - each optimized for its specific function without compromising the other

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3348859B1chain
Publication Date: 2020.09.23 KMC CHAIN INDUSTRIAL CO LTD
  • EP3348859B1 patent drawingFigure 1
  • EP3348859B1 patent drawingFigure 2
  • EP3348859B1 patent drawingFigure 3

AI summary

A chain includes an inner link unit (92) . The inner link unit (92) includes an inner chain plate (1), and an accompanying chain plate (2) spaced apart from the inner chain plate (1). The inner chain plate (1) has two spaced-apart end sections (11), and a connecting section (12) interconnecting the end sections (11) and having a first recess (121) . The first recess (121) has two first edges (123) parallel to each other. The accompanying chain plate (2) has a second recess (21) that has two second edges (211) parallel to each other. The first edges (123) of the first recess (121) and the second edges (211) of the second recess (21) extend in the same direction.