Pneumatic Tire Carcass Reinforcement Angle Optimization
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Solution Overview
Problem
Cross-ply tires used in high-load applications, such as underground mining, face challenges with tear propagation resistance and cut resistance due to stress-neutral design that leads to crack propagation and increased vulnerability to injuries.
Innovation Solution
Adjusting the angle of tire reinforcements relative to the circumferential direction to between 28° and 34° for a width-to-height ratio of 1, and 26° to 32° for a ratio of 0.85, making the carcass stiffer and reducing stress, while using multiple carcass plies and intermediate layers to enhance stability and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the tire is designed with stress-neutral reinforcement angles (20° to 45°) to allow uniform expansion when inflated, then the tire achieves stable shape and even rubber material expansion, but the tread becomes more susceptible to cut injuries and crack propagation increases
Solution Approach 1:
The patent changes the reinforcement angle parameter from the conventional stress-neutral range (20°-45°) to a smaller range (28°-34° for ratio 1, 26°-32° for ratio 0.85). This parameter change transforms the tire from stress-neutral to stress-negative design, where the tread is compressed rather than stretched during inflation, significantly improving cut resistance and stopping crack propagation while maintaining acceptable shape stability.
2Reliability
If the reinforcement angle is reduced to improve cut resistance and stop crack propagation, then the tread becomes stiffer and more resistant to injuries, but the tire no longer expands uniformly when inflated
Solution Approach 1:
The patent applies parameter changes by reducing the reinforcement angle below the stress-neutral threshold, accepting non-uniform expansion as a trade-off to achieve the primary goal of improved tread cut resistance and crack propagation resistance.
Solution Approach 2:
The patent converts the harmful effect of stress concentration at smaller angles into a beneficial effect. The stress that would normally concentrate and cause crack propagation is instead used to compress the tread, closing cracks and preventing their propagation, thereby improving tire reliability in harsh mining conditions.
3Strength
If multiple carcass plies (2 to 26 layers) are used to enhance tire stability and load-bearing capacity, then the tire can withstand high loads and overloads, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies local quality by varying the reinforcement angle in different carcass plies. While all plies use the same angle range (28°-34° or 26°-32°), this consistent local configuration across multiple plies creates cumulative stiffness and strength effects that improve cut resistance and load-bearing capacity without requiring each individual ply to be structurally complex.
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 reduces rolling resistance, fuel consumption, and susceptibility to cuts by compressing cracks instead of expanding them, resulting in a more durable and resistant tread.
Implementation Method 1
the angle that the reinforcement members enclose with the circumferential direction at the zenith of the tire is between 28° and 34° in a tire with a ratio of cross-sectional width to cross-sectional height of 1, in a tire with a ratio of cross-sectional width to cross-sectional height of 0.85 is between 26° and 32°
Data Source
Figure 1
AI summary
The invention relates to a beltless pneumatic tire for a vehicle, having a ratio of cross-sectional width to cross-sectional height (determined as per E.T.R.T.O. standards) of 1 or 0.85 and comprising a carcass having a diagonal design, which carcass has a plurality of carcass inserts (6, 6'), which are arranged one over the other and which have reinforcements (7), which are embedded in a rubber matrix, extend parallel to each other, and are made of a textile material, wherein the reinforcements (7) in carcass inserts (6, 6') extending adjacent to each other are arranged in a cross arrangement and extend at an acute angle to the circumferential direction at the tire zenith, which acute angle is identical in all carcass inserts (6, 6'). The angle (alpha, beta) included by the reinforcements (7) with the circumferential direction at the zenith of the tire is between 28° and 34° for a tire having a ratio of cross-sectional width to cross-sectional height of 1 and between 26° and 32° for a tire having a ratio of cross-sectional width to cross-sectional height of 0.85.