Agricultural Tire Tread Blocks for Soft Ground Traction

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Solution Overview

Problem

Existing agricultural vehicle treads face challenges in achieving optimal traction performance on soft ground without compromising wear resistance, comfort, and road travel capabilities.

Innovation Solution

A tread design featuring radially extending blocks with transverse incisions and lateral sculpture elements, where the leading face has a greater radial height and specific angular orientations, enhancing traction on soft ground while maintaining road performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional lugs with symmetrical arrangement and uniform height are used, then the tread maintains good road travel capability and wear resistance, but soft ground traction performance is insufficient

Engineering Contradiction:
Improvesoft ground tractionVSAvoidwear resistance and road travel capability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The tread pattern elements feature asymmetric design where the leading face (attack face) has a greater radial height than the trailing face. This asymmetry allows the leading face to penetrate soft ground more effectively for improved traction, while the shorter trailing face reduces resistance during the exit phase. The asymmetric configuration resolves the contradiction by optimizing ground engagement without compromising overall tread durability

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention applies different radial heights to different portions of the tread pattern elements. The leading face has a greater radial height (HRA) compared to the trailing face (HRF), creating localized variations in ground penetration capability. This local quality differentiation allows the tread to achieve superior soft ground traction through enhanced ground engagement at the leading edge, while maintaining adequate wear resistance across the entire tread structure

Inventive Principle:
Principle #3Local quality

2Productivity

If deeper grooves are introduced to improve soft ground traction, then traction performance increases, but rolling resistance and vibration increase on road surfaces

Engineering Contradiction:
Improvesoft ground tractionVSAvoidrolling resistance
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The tread pattern incorporates transverse grooves that are inclined relative to the radial direction, creating a dynamic configuration that adapts to different operating conditions. The grooves have a radial depth (PR) of at least 50% of HRA, providing sufficient ground engagement for soft terrain traction while the inclined orientation reduces the effective depth encountered during road rolling, thereby limiting energy losses from excessive deformation

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention optimizes the radial depth parameter of the transverse grooves to be at least 50% of the leading face height (HRA). This specific parameter configuration allows the grooves to provide adequate ground penetration and traction on soft surfaces while controlling the depth to minimize rolling resistance and vibration on harder road surfaces. The angular orientation parameters (α between 93-105 degrees, β between 5-35 degrees) further refine the groove geometry to balance traction and rolling resistance

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the tread pattern is optimized for soft ground entry, then traction improves, but the tread structure becomes more complex

Engineering Contradiction:
Improvetraction forceVSAvoidtread pattern complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The tread is divided into multiple discrete pattern elements (lugs, blocks, or bars) arranged in circumferential rows. Each element is separated by longitudinal and transverse grooves, creating a segmented structure. This segmentation allows independent optimization of each element's geometry (leading face height, contact face angle) to maximize traction while keeping individual elements simple in form, thereby managing overall complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each tread pattern element features asymmetric geometry with a leading face of greater radial height than the trailing face. This asymmetric design is applied consistently across all elements, creating a unified yet complex-optimized pattern. The asymmetry provides superior ground engagement capability while the regular repetition of this optimized element throughout the tread maintains manufacturing feasibility and structural coherence

Inventive Principle:
Principle #4Asymmetry

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

Significant improvement in soft ground traction, with gains of 10-55% compared to conventional treads, without adversely affecting wear resistance or road travel capabilities.

Implementation Method 1

the leading face having, from the bearing surface, a radial height HRA greater than the radial height HRF of the trailing face... the contact face being oriented at an angle α relative to the radial direction Z, α being between 93 and 105 degrees

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

Grooves generate a significant reduction in the compression and shear rigidities of the tread since these grooves delimit portions of material that can deform much more significantly than the portions delimited by incisions

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 3

said lateral sculpture elements comprising a contact face, a leading face and a trailing face, said leading face being inclined at an angle γ backward relative to the radial direction Z depending on the rolling direction of the tread, the angle γ being between 50 degrees and 75 degrees

Methodology Applied
Scientific EffectForce distribution: Force

Data Source

PatentEP3880494B1Tread for an agricultural vehicle
Publication Date: 2025.07.02 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP3880494B1 patent drawingFigure 1~2
  • EP3880494B1 patent drawingFigure 3~5
  • EP3880494B1 patent drawingFigure 6~8

AI summary

The invention relates in particular to a tread (2) for the drive axle of an agricultural machine, said tread comprising tread pattern elements (21, 41) extending radially outwards from a bearing surface (22), said tread pattern elements comprising, in the central part of the tread, a series of blocks (41) that are juxtaposed with one another in the longitudinal direction, said tread pattern blocks being separated from one another by transverse cuts (42), said blocks having, in the rolling direction (15), a leading face, a contact face and a trailing face, said leading face having a radial height greater than the radial height of the trailing face, the contact face being oriented at an angle α with respect to the radial direction Z, α being between 93 and 105 degrees, and the radial depth PR of the transverse cuts (42) being at least equal to 50% of the radial height of the leading face, the width of said blocks making up at least 15% of the width of the tread.