Segmented Crawler Lugs with Asymmetric Angles for Mud Discharge

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Solution Overview

Problem

Rubber crawlers experience continuous mud lodging along the peripheral direction when driving on rough ground with clayey soil, affecting traction performance.

Innovation Solution

A crawler design featuring an elastic material with projections on the inner peripheral face and lugs on the outer peripheral face, angled to enhance earth discharging and traction, where the lugs extend at a larger acute angle on the outer side than the central line side, and their end portions overlap to prevent mud lodging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lugs are disposed with end portions on the central line side adjacent to each other to prevent mud lodging, then mud lodging is suppressed, but the structural complexity increases

Engineering Contradiction:
Improvemud lodging suppressionVSAvoidlug arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The crawler body is divided into multiple lugs that are segmented and distributed at specific intervals along the peripheral direction. Each lug is positioned at a determined distance from adjacent lugs, creating discrete earth-discharging passages that effectively prevent continuous mud lodging while maintaining structural manageability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lugs are arranged asymmetrically with respect to the central line, with end portions on the central line side being adjacent to each other while other portions are spaced apart. This asymmetric configuration optimizes mud prevention at critical areas without requiring complete coverage, reducing overall structural complexity

Inventive Principle:
Principle #4Asymmetry

2Productivity

If lugs extend at a larger acute angle on the outer side than on the central line side to improve earth discharging, then earth discharging ability is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveearth discharging abilityVSAvoidlug angle precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

Different portions of the lugs have different extension angles adapted to their specific functions. The outer side portions extend at larger acute angles to maximize earth discharging efficiency, while the central line side portions have smaller angles suitable for their position near the crawler body, optimizing performance without uniform complexity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The lug geometry is pre-designed with specific angle variations during the manufacturing planning stage. By predetermined the angle differences between outer and central portions before production, the manufacturing process follows a clear specification, reducing actual manufacturing precision requirements despite the complex geometry

Inventive Principle:
Principle #10Preliminary action

3Productivity

If projections are provided on the inner peripheral face at spaced apart positions to improve traction, then traction performance is improved, but the device complexity increases

Engineering Contradiction:
Improvetraction performanceVSAvoidprojection arrangement complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Multiple projections are segmented and distributed at specific intervals along the inner peripheral face in the peripheral direction. This segmentation provides multiple traction contact points with the ground, improving overall traction performance while keeping each individual projection simple in structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The projections serve multiple functions: they provide traction enhancement by engaging with the ground surface, and they contribute to the overall structural framework of the crawler body. This multi-functionality improves traction without requiring separate dedicated components, reducing device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design improves earth discharging ability and traction performance by increasing the force component applied to the soil and preventing mud lodging, thereby enhancing the crawler's ability to navigate rough terrain.

Implementation Method 1

a crawler body (12) that is formed from an elastic material in an endless shape

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

extend at an angle to the crawler peripheral direction from an end portion on the central line side toward the crawler width direction outer side and toward an opposite side to a crawler rotation direction with a larger angle at an acute angle side with respect to the crawler peripheral direction

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3133000B1Endless track
Publication Date: 2018.07.11 BRIDGESTONE CORP
  • EP3133000B1 patent drawingFigure 1
  • EP3133000B1 patent drawingFigure 2
  • EP3133000B1 patent drawingFigure 3

AI summary

A rubber crawler that has a specified rotation direction. The rubber crawler includes a crawler body, rubber projections that project out from an inner peripheral face, and lugs. The lugs project out from an outer peripheral face, are allocated to one side and another side in the crawler width direction so as to be alternately disposed on progression along the crawler peripheral direction on either side of the central line, extend at an angle to the crawler peripheral direction from an inner side end portion toward the crawler width direction outer side and toward an opposite side to a crawler rotation direction with a larger angle at an acute angle side with respect to the crawler peripheral direction on the crawler width direction outer side than on the central line side; have inner side end portions of lugs adjacent to each other in the crawler width direction respectively overlapping a single projection of the projections, and are disposed at positions separated in the crawler width direction with the inner side end portions adjacent to each other in the crawler width direction respectively overlapping each other when viewed along the crawler width direction.