Undercarriage Support Roller Geometry for Track Chain Stability

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Solution Overview

Problem

Earth moving and construction equipment with track chains experience backbending and bounce issues on uneven terrain, leading to increased wear and maintenance needs, which can result in downtime and economic losses.

Innovation Solution

An undercarriage configuration with a specific arrangement of bottom support rollers, wheels, and transitional zones that supports the track chain, optimizing the ratios of distances between these components to prevent backbending and reduce bounce, while maintaining component durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If hydraulic cylinders are used to increase track tension, then backbending and bounce are reduced, but the wear rate of track chain components increases

Engineering Contradiction:
Improvetrack chain stabilityVSAvoidcomponent wear
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent changes the geometric parameters of the undercarriage system by optimizing the ratio of bottom support roller platform distance to wheel pitch distance (0.65-0.85) and roller spacing to link pitch distance (0.75-1.50). This geometric optimization provides adequate track support and prevents backbending without requiring excessive tension, thereby reducing component wear while maintaining stability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If increased tension is applied to the track chain, then backbending is prevented, but maintenance frequency increases due to faster wear

Engineering Contradiction:
Improvetrack chain performanceVSAvoidmaintenance downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent optimizes geometric parameters including the ratio of bottom support roller platform distance to wheel pitch distance (0.65-0.85) and roller spacing to link pitch distance (0.75-1.50). These parameter changes enable the track chain to maintain proper support and tension distribution, preventing backbending and reducing the frequency of maintenance interventions.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the machine operates on rough terrain, then mobility and obstacle crossing ability are improved, but track chain backbending and bounce increase

Engineering Contradiction:
Improveterrain adaptabilityVSAvoidtrack chain stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by positioning bottom support rollers at specific intervals along the track chain, with the first bottom support roller located within 1.5 link pitch distances from the drive sprocket. This localized support arrangement provides targeted stabilization at critical points where backbending is most likely to occur during operation on rough terrain.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent optimizes geometric parameters including the ratio of bottom support roller platform distance to wheel pitch distance (0.65-0.85) and roller spacing to link pitch distance (0.75-1.50). These parameter optimizations enable the track chain to maintain stability and resist backbending while operating on varied and rough terrain conditions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3508402B1Undercarriage support for a track chain
Publication Date: 2021.01.27 CATERPILLAR INC
  • EP3508402B1 patent drawingFigure 1
  • EP3508402B1 patent drawingFigure 2
  • EP3508402B1 patent drawingFigure 3

AI summary

An undercarriage (200) includes a plurality of bottom support rollers (212) defining a bottom support roller platform distance (226) and front and rear wheels (202a, 202b) defining a wheel pitch distance (228), and a track chain (204) defining a link pitch distance (222) and a ratio of the bottom support roller platform distance (226) to the wheel pitch distance (228) ranges from 0.70 to 0.95 and a ratio of the roller spacing distance (240) to the link pitch distance (222) ranges from 0.75 link pitch distance (222) to 1.50 link pitch distances (222).