Rubber Crawler Core Recess Structure for Easier Sprocket Winding

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Solution Overview

Problem

Conventional rubber crawlers experience high flexural rigidity when bent around a sprocket due to narrow clearance between adjacent core projections, making it difficult to wind the crawler and increasing the loss of driving force.

Innovation Solution

The rubber crawler design includes cores with first and second projections featuring recesses on their facing surfaces, allowing for an enlarged clearance when bent, reducing the risk of contact and maintaining rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If cores are arranged closely together to prevent side slip, then lateral stability is improved, but flexural rigidity becomes too high making it difficult to wind around sprockets

Engineering Contradiction:
Improvelateral stabilityVSAvoidwinding ease
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The core structure incorporates projections with different local properties: the main body provides rigidity for lateral stability, while the projections include recesses that create localized flexibility zones. These recesses allow the core to deform locally during bending, enabling the crawler to wind around sprockets without excessive resistance while maintaining overall structural integrity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The core is divided into multiple functional segments: a base portion for structural support, horn portions for engagement, and projections with recesses for flexibility. This segmentation allows different parts of the core to perform different functions - the base and horn portions maintain rigidity for preventing side slip, while the projections with recesses provide the necessary flexibility for bending around sprockets.

Inventive Principle:
Principle #1Segmentation

2Strength

If clearance between projections of adjacent cores is narrow to maintain rigidity, then structural strength is improved, but driving force loss increases due to excessive contact

Engineering Contradiction:
Improvestructural strengthVSAvoiddriving force loss
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The projection structure uses local quality by creating recesses in specific areas of the projections. These recesses are positioned to reduce contact between adjacent cores during bending, thereby reducing energy loss. The remaining solid portions of the projections maintain structural strength and prevent side slip, while the recessed areas provide clearance that reduces friction and driving force loss.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If cores are positioned close together to prevent side slip, then lateral stability is improved, but flexural rigidity becomes excessive preventing proper winding

Engineering Contradiction:
Improvelateral stabilityVSAvoidflexural rigidity
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The core projections incorporate recesses that create flexible zones within the otherwise rigid core structure. These recesses act like thin film regions that can deform easily during bending, allowing the core to flex when the crawler winds around sprockets. The base portion and horn portions maintain rigidity for lateral stability, while the recessed projections provide the necessary flexibility.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP4321416B1Rubber crawler and core
Publication Date: 2026.05.06 BRIDGESTONE CORP
  • EP4321416B1 patent drawingFigure 1
  • EP4321416B1 patent drawingFigure 2
  • EP4321416B1 patent drawingFigure 3

AI summary

A rubber crawler 1 includes an endless crawler body 12 made of rubber, and a plurality of cores 13 embedded in the crawler body and arranged along the crawler circumferential direction, where at least a first projection on the crawler width direction first side in a pair of first projections of each core has a first recess R1 on a surface facing a second projection of another core of the surfaces on the two sides in the crawler width direction.