Off-Road Tire Tread With Variable Depth Grooves
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Solution Overview
Problem
Tires for civil engineering vehicles face challenges in maintaining grip performance and reducing operating temperature in high-wear conditions due to harsh ground stress and temperature increases from cyclic deformations, especially when used in off-road applications.
Innovation Solution
A tread pattern design featuring a combination of transverse, oblique, and circumferential cuts with varying depths and orientations, including a central narrow zigzag groove and intermediate regions with oblique or transverse narrow grooves, optimized for contact patch performance and thermal ventilation, along with the use of multiple materials for enhanced wear resistance and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tread thickness is increased to at least 60 mm for civil engineering vehicles, then the durability and resistance to harsh ground conditions are improved, but the operating temperature increases due to cyclic deformations
Solution Approach 1:
The tread incorporates a porous structure with cells distributed throughout the tread thickness, creating internal voids that facilitate heat dissipation. This porous architecture allows thermal energy to be conducted away from the contact patch through the tread body, reducing operating temperature while preserving the overall tread thickness for durability.
Solution Approach 2:
The invention transitions from surface-level thermal management to three-dimensional thermal dissipation by embedding a network of porous cells throughout the tread volume. This volumetric approach to heat management enables thermal energy to be distributed and dissipated throughout the entire tread structure rather than just at the surface.
2Temperature
If wide grooves are created in the tread for thermal ventilation, then the operating temperature is reduced, but the grip performance deteriorates due to reduced contact area
Solution Approach 1:
The porous structure is distributed selectively throughout different regions of the tread, with varying cell densities and configurations tailored to local thermal requirements. This localized optimization allows thermal ventilation where needed while preserving continuous contact areas for grip, creating non-uniform thermal management that adapts to local conditions.
Solution Approach 2:
The tread is divided into multiple discrete porous cells separated by solid tread material. This segmentation creates a distributed network of thermal pathways that can operate independently, allowing heat dissipation through multiple parallel channels without creating large continuous voids that would compromise grip.
3Reliability
If narrow sipes are created in the tread pattern, then the grip performance is improved through edge corners, but the tread stiffness is reduced when opposing walls contact
Solution Approach 1:
The porous cells are positioned and sized to create localized flexibility in specific regions while maintaining structural integrity in load-bearing areas. This spatial variation in porosity allows the tread to exhibit region-specific mechanical properties, providing flexibility where grip is needed while maintaining stiffness where structural support is required.
Data Source
AI summary
Tread (1) of a tire for an off-road vehicle, with total width (W) and total thickness of wearable material at least equal to 60 mm. The tread is delimited axially by shoulder regions (5) provided with grooves (7). This tread (1) comprises, in central region (6), narrow groove (61) and, between each shoulder region (5) and the central region (6), an intermediate region (4) in which there are formed a plurality of oblique or transverse narrow grooves (411, 412). Narrow groove (61) of the central part is made up of first narrow-groove parts (611) of depth (P1) and of second narrow-groove parts (612) of depth (P2). Depth (P1) is greater than depth (P2). Narrow grooves (411, 412) of one same intermediate region comprise, in the circumferential direction, an alternation of narrow grooves (411) of first depth (P11) and of narrow grooves (412) of second depth (P22).