Tread Ventilation Cavity Geometry for Heat and Debris Management
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Solution Overview
Problem
Tires for civil engineering and off-road vehicles with thick treads face premature damage due to heat generation from hysteresis in rubber materials, and existing ventilation cavities can capture foreign objects, leading to potential damage from retained debris.
Innovation Solution
The tire design features ventilation cavities with a specific geometry, including a first part with a mean relief angle of at least 20 degrees and a second part with a mean relief angle of up to 15 degrees, intersecting the tread surface along a closed contour, with a maximum cross-sectional area of the second part being at least 40% of the first part, and a unique shape that reduces the risk of foreign body retention while enhancing heat exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ventilation cavities are formed in the tread to evacuate heat, then temperature reduction is improved, but foreign object retention risk increases
Solution Approach 1:
The ventilation cavity is divided into two distinct parts: a first part with a wide opening that captures foreign objects, and a second part with a narrower section that prevents retention while allowing heat evacuation. This segmentation resolves the contradiction by creating different functional zones within the same cavity structure.
Solution Approach 2:
Instead of making the cavity uniformly wide to prevent foreign object retention (which would reduce ventilation efficiency), the invention inverts the approach by creating a narrow section within the cavity. This narrow section allows heat to pass through while preventing foreign objects from being retained, thus solving the contradiction through reverse thinking.
2Productivity
If cavity opening size is increased to improve ventilation, then heat exchange efficiency is improved, but foreign object capture increases
Solution Approach 1:
The cavity opening is segmented into a first part with a larger cross-sectional area for efficient heat exchange and a second part with a reduced cross-sectional area that acts as a filter. This segmentation allows the system to achieve both high ventilation efficiency and foreign object prevention.
Solution Approach 2:
Different sections of the cavity have different geometric properties: the first part has a larger opening optimized for heat exchange, while the second part has a narrower section optimized for preventing foreign object retention. This local differentiation of properties resolves the contradiction between ventilation efficiency and foreign object capture.
3Strength
If tread thickness is increased to improve load bearing, then strength is improved, but heat generation increases
Solution Approach 1:
The thick tread incorporates ventilation cavities that create a porous internal structure. This allows heat generated by hysteresis in the thick rubber material to evacuate through the cavities, preventing heat accumulation while maintaining the load-bearing advantage of the thick tread design.
Solution Approach 2:
The thick tread is effectively segmented by the ventilation cavities into regions separated by air gaps. This segmentation reduces the continuous rubber mass that generates heat through hysteresis, allowing the thick tread to maintain strength while reducing overall heat generation and improving heat evacuation.
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 effectively reduces heat levels and minimizes the risk of foreign object retention, promoting efficient ventilation and wear distribution while maintaining tire integrity.
Implementation Method 1
one of the functions of said cavities being to create ventilation in order to evacuate heat generated during running
Implementation Method 2
this heating within the material is related to hysteresis characteristics of the rubber materials of which this tread is made
Data Source
AI summary
Tread (1) having tread surface (10) axially bounded by edge parts (11), and provided with cuts (3, 4) delimiting material parts forming raised elements (2), each raised element (2) comprising contact face (20), there being formed, in a plurality of raised elements (2), a ventilation cavity (5) having a depth at least equal to 70% of the thickness of the tread material to be worn away, each ventilation cavity (5) being delimited by wall surface (50) ending at bottom surface (530). Each ventilation cavity (5) comprises first cavity part (51) continued into the depth by second cavity part (52). The first cavity part (51) is situated between the tread surface and intermediate depth level H1 situated at between 30% and 70% of maximum depth H of ventilation cavity (5), the mean relief angle A of the wall is at least equal to 20 degrees. In the second cavity part (52), mean relief angle B of the wall is at most equal to 15 degrees.