Track Joint Bushing Design for Wear Reduction

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Solution Overview

Problem

Existing track joint assemblies for earth-working machines, such as loaders and excavators, face high maintenance costs due to extreme wear from abrasion and impacts, with complex and costly manufacturing processes, particularly in creating lubricant channels and accommodating large inserts or collars.

Innovation Solution

The track joint assembly features a bushing with different axial end portions and a middle portion, allowing for direct press-fits with links and pins, reducing material requirements and manufacturing complexity, and utilizing lubricating fluids in separate cavities with thrust rings to minimize wear and friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lubricant channels are manufactured in pins to deliver lubricant to gaps, then lubrication is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvelubrication effectivenessVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts the lubricant delivery function from the pin by removing the internal lubricant channel. Instead, lubricant is delivered externally through gaps between the pin and bushing, eliminating the need for complex internal channel machining while maintaining lubrication effectiveness

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces seals as intermediary components between the pin and bushing. These seals create controlled gaps that facilitate lubricant delivery to the friction surfaces without requiring internal channels in the pin, thus simplifying manufacturing while ensuring reliable lubrication

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If large inserts and collars are accommodated in links, then structural strength is improved, but material usage and manufacturing cost increase

Engineering Contradiction:
Improvestructural strengthVSAvoidmaterial usage
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The invention merges the functions of separate inserts and collars into a single integrated bushing structure. The bushing directly engages with both the pin and link, eliminating the need for additional inserts and collars, thus reducing material usage while maintaining structural strength

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bushing is designed as a multi-functional component that simultaneously provides bearing support, structural reinforcement, and sealing functions. This universal component replaces multiple specialized parts (inserts, collars), reducing overall material consumption while achieving the required structural strength

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

This configuration enhances durability and strength, reduces material usage and manufacturing costs, and facilitates efficient lubrication, resulting in a more cost-effective and reliable track joint assembly.

Implementation Method 1

utilizing lubricating fluids in separate cavities with thrust rings to minimize wear and friction

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

utilizing lubricating fluids in separate cavities with thrust rings to minimize wear and friction

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3038888B1Track joint assemblies
Publication Date: 2018.10.10 CATERPILLAR INC
  • EP3038888B1 patent drawingFigure 1
  • EP3038888B1 patent drawingFigure 2
  • EP3038888B1 patent drawingFigure 3

AI summary

Disclosed are various exemplary embodiments of a track joint assembly. In one exemplary embodiment, the track joint assembly may include a first link having a first bore. The track joint assembly may also include a second link having a second bore including first and second portions. The first and second portions may have different diameters. In addition, the track joint assembly may include a solid pin positioned at least partially within the first bore. The track joint may also include a bushing positioned coaxially around the pin. The bushing may include an axial end portion disposed in and contacting the first portion of the second bore. The bushing may also include an axial end-adjacent portion disposed in and contacting the second portion of the second bore. An outer diameter of the end-adjacent portion may be larger than an outer diameter of the end portion.