Urban Bus Tire Tread with Zigzag Grooves for Wet and Dry Grip
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Solution Overview
Problem
Heavy-duty urban vehicle tires face challenges in maintaining grip on both dry and wet surfaces due to their low volumetric void ratio, which affects safety and traction.
Innovation Solution
The tire features a tread with at least two zigzag grooves oriented obliquely, each with a depth of at least 7 mm and a taper angle of at least 10°, along with longitudinal and oblique portions that enhance both transverse and longitudinal grip, and a network of cuts that reduces the volumetric void ratio while maintaining effective water discharge and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the volumetric void ratio is reduced to extend tire life, then wear resistance is improved, but grip on wet ground deteriorates
Solution Approach 1:
The tread is segmented into two distinct types of cuts: grooves (wide cuts for water storage and discharge) and sipes (narrow cuts for edge-corner grip). This segmentation allows the tire to maintain low overall void ratio while having strategically placed water management features. The grooves are distributed to provide adequate water discharge paths without requiring high volumetric void ratio, and sipes provide additional grip enhancement with minimal volume consumption.
Solution Approach 2:
Different regions of the tread have different cut characteristics optimized for their specific functions. Grooves are positioned in areas requiring water discharge capability, while sipes are distributed to enhance grip in contact patches. The varying depth, width, and orientation of cuts in different tread zones allow localized optimization of both water management and grip performance while maintaining overall low void ratio for extended tire life.
2Duration of action of stationary object
If the volumetric void ratio is reduced to extend tire life, then wear resistance is improved, but grip on dry ground deteriorates
Solution Approach 1:
The tread pattern segments grip-enhancing features into sipes with edge corners that provide mechanical interlocking with the ground surface. These sipes are strategically positioned to maximize dry grip through edge-corner effects without requiring large volumes that would reduce tire life. The segmentation allows concentrated grip enhancement in key contact areas rather than uniform distribution.
Solution Approach 2:
The sipes and grooves feature asymmetric geometries with specific edge corner configurations that optimize dry ground grip. The non-uniform depth profiles, varying widths, and strategic positioning create asymmetric contact characteristics that enhance mechanical interlocking with dry surfaces while minimizing material removal and maintaining low void ratio for extended tire life.
3Reliability
If deep grooves are added to improve water discharge, then grip on wet ground is improved, but volumetric void ratio increases
Solution Approach 1:
Instead of providing excessive water discharge capacity throughout the entire tread, the invention uses partial action by positioning grooves strategically in areas where water accumulation is most critical. The groove depth and distribution are optimized to provide sufficient water discharge for safety without creating excessive void volume. This partial optimization approach achieves adequate wet grip performance while maintaining low overall volumetric void ratio.
4Reliability
If more cuts are added to enhance grip, then grip capability is improved, but wear resistance deteriorates
Solution Approach 1:
The cut network is segmented into grooves and sipes with different functions and volume characteristics. Grooves provide water management with moderate volume consumption, while sipes provide grip enhancement with minimal volume. This segmentation allows the tire to achieve comprehensive grip capability through functional differentiation rather than uniform increase in total cut volume, thereby preserving wear resistance.
Solution Approach 2:
The invention optimizes multiple parameters of the cuts including depth, width, orientation, and distribution patterns. By carefully controlling these parameters, the design achieves maximum grip effectiveness from each unit of void volume. The parameter optimization ensures that grip enhancement is achieved through efficient geometric configuration rather than simply increasing the total volume of cuts, thus maintaining wear resistance.
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 design significantly improves grip and traction, reduces rolling resistance, and extends tire life with a 40% increase in grip capability and 5% reduction in rolling resistance, while maintaining a low volumetric void ratio.
Implementation Method 1
the discharge of water, which might be present on the ground, by the cuts of the tread does not require a high volume of cuts
Implementation Method 2
the intersections with the tread surface, or edge corners, contribute to grip on wet ground by virtue of an edge-corner effect in the contact patch which makes it possible to break the film of water present on the ground
Implementation Method 3
grip on dry ground and on wet ground is a fundamental performance desired by tire manufacturers
Data Source
AI summary
A tire (1) for a heavy-duty vehicle for urban use and aims to improve the grip of the tire. The tire has a tread (2) which has at least two zigzag and mutually parallel wide cuts (41), referred to as grooves, each zigzag groove (41) is made up of alternating longitudinal portions (411), which are parallel to a longitudinal direction (XX′) of the tire, and oblique portions (412), each of which forms one and the same angle A with the longitudinal direction (XX′) at least equal to 15°, the depth of each zigzag groove (41) is at least equal to 7 mm, and the taper angle of each wall that delimits each zigzag groove (41) is at least equal to 10°.