Variable Hardening Depth in Track Link for Retarding Wear Scallops

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Solution Overview

Problem

Existing ground-engaging track systems experience uneven wear patterns due to harsh operating conditions, leading to reduced service life and increased maintenance costs, as the current strategies for material selection and manufacturability are not optimized for economics and durability.

Innovation Solution

The track links feature a longitudinally non-uniform material interface with a sacrificial higher hardness material transitioning from the upper rail surface to a lower hardness material, varying in depth to retard penetration of wear scallops and distribute wear more uniformly, thereby extending service life and improving ride quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a uniform depth of sacrificial higher hardness material is applied across the entire upper rail surface, then manufacturing is simplified, but wear distribution remains uneven leading to premature failure at high-stress zones

Engineering Contradiction:
Improveservice lifeVSAvoidmaterial interface complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by varying the depth of the sacrificial higher hardness material along the longitudinal axis of the track link. The material interface transitions from a first depth at the leading end to a second depth at the trailing end, creating zones of different hardness depths optimized for their specific functional requirements. This resolves the contradiction by improving reliability through targeted wear protection while accepting increased manufacturing complexity as a necessary trade-off.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the upper rail surface into multiple zones along the longitudinal axis, each with a different depth of sacrificial higher hardness material. This segmentation allows each zone to be optimized for its specific wear conditions, with the material interface creating distinct regions that address localized wear patterns. The segmentation approach improves overall reliability by preventing premature failure at any single zone while managing the complexity through systematic zonation.

Inventive Principle:
Principle #1Segmentation

2Reliability

If higher hardness material is applied to the upper rail surface to resist wear, then wear resistance improves, but the track link becomes more susceptible to brittle fracture and impact damage

Engineering Contradiction:
Improvewear resistanceVSAvoidimpact resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs composite materials by combining sacrificial higher hardness material with lower hardness base material in a layered structure. The higher hardness material provides wear resistance at the surface, while the lower hardness material beneath absorbs impact energy and prevents brittle fracture. This composite approach resolves the contradiction by allowing both wear resistance and impact resistance to coexist in different layers of the same component.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent implements beforehand cushioning by placing the lower hardness material beneath the higher hardness material to act as a cushioning layer. This underlying softer material is positioned in advance to absorb impact forces before they can cause brittle fracture in the harder surface layer. The cushioning effect prevents catastrophic failure while maintaining the wear resistance of the surface material.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Duration of action of moving object

If the sacrificial higher hardness material has uniform depth, then manufacturing cost is reduced, but wear scallops penetrate deeper into the lower hardness material reducing service life

Engineering Contradiction:
Improveservice lifeVSAvoidmanufacturing complexity
Core Design Contradiction:
Duration of action of moving objectVSEase of manufacture

Solution Approach 1:

The patent applies local quality by varying the depth of the sacrificial higher hardness material along the longitudinal axis of the track link. The material interface transitions from a first depth at the leading end to a second depth at the trailing end, creating zones of different hardness depths optimized for their specific functional requirements. This resolves the contradiction by improving reliability through targeted wear protection while accepting increased manufacturing complexity as a necessary trade-off.

Inventive Principle:
Principle #3Local quality

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

This approach effectively prolongs the service life of track systems by uniformly distributing wear and reducing the severity of scallop formation, maintaining ride quality and delaying the need for replacement or servicing.

Implementation Method 1

The sacrificial higher hardness material has a varying depth from the upper rail surface retarding penetration of a wear scallop resulting from the contact into the lower hardness material

Methodology Applied
Scientific EffectWear: Wear

Data Source

PatentEP3027493B1Variable hardening depth in track link for a ground-engaging track
Publication Date: 2019.01.16 CATERPILLAR INC
  • EP3027493B1 patent drawingFigure 1
  • EP3027493B1 patent drawingFigure 2~3
  • EP3027493B1 patent drawingFigure 4~5

AI summary

A track link (24) for a ground-engaging track (16) includes an elongate link body (24) having a lower hardness material (34) forming a lower mounting surface (26) for mounting a track shoe (28), and a sacrificial higher hardness material (36) forming an upper rail surface (30) for contacting rotatable track engaging elements (11, 15). The lower hardness and higher hardness materials (34, 36) transition at a material interface (38) within the elongate link body (24), and the material interface (38) is longitudinally non-uniform, such that the sacrificial higher hardness material (36) has a varying depth from the upper rail surface (30) to retard scalloping.