Heavy Duty Tire Tread Zigzag Grooves Chipping Rolling Resistance
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Solution Overview
Problem
Heavy duty pneumatic tires face a trade-off between chipping resistance and rolling resistance, with increased chipping resistance leading to higher rolling resistance due to tread block deformation, and reduced lateral grooves improving rolling resistance but compromising chipping resistance.
Innovation Solution
The tire features a tread portion with circumferentially and continuously extending zigzag shaped main grooves, lateral grooves, and land portions forming block elements, along with specific groove and sipe configurations to enhance both chipping and rolling resistance, including first and second groove bottom sipes, and connecting portions that adjust contact pressure and deformation to improve wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a heavy duty pneumatic tire has many lateral grooves to improve chipping resistance, then chipping resistance is improved, but rolling resistance increases due to large energy loss from tread block deformation
Solution Approach 1:
The patent changes the geometric parameters of the tread pattern by introducing zigzag-shaped main grooves with specific amplitudes and pitches. The middle main groove has a larger zigzag amplitude than crown and shoulder main grooves, creating block elements with optimized dimensions that reduce deformation energy loss while maintaining chipping resistance
Solution Approach 2:
The patent uses zigzag-shaped curved grooves instead of straight grooves. The continuous zigzag pattern creates smooth transitions and rounded block element shapes that reduce stress concentration and deformation during rolling, thereby lowering rolling resistance while maintaining structural integrity for chipping resistance
2Loss of energy
If a heavy duty pneumatic tire has fewer lateral grooves to reduce rolling resistance, then rolling resistance is reduced, but chipping resistance decreases where tread rubber easily chips under ground contact pressure
Solution Approach 1:
The patent applies different zigzag amplitudes to different regions of the tread. The middle main groove (in the intermediate region) has a larger amplitude to create smaller block elements for reduced rolling resistance, while crown and shoulder main grooves have smaller amplitudes to maintain larger block elements for chipping resistance in high-stress areas
3Loss of energy
If the middle main groove has a larger zigzag amplitude to reduce rolling resistance through smaller block elements, then rolling resistance is reduced, but the structural integrity for chipping resistance may be compromised
Solution Approach 1:
The patent optimizes the pitch parameter (distance between adjacent block elements) in the intermediate region to fall within 40-50 pitches, creating block elements with circumferential lengths of 85-95% of the pitch. This specific parameter range ensures reduced deformation energy loss while maintaining sufficient structural integrity
Solution Approach 2:
The patent segments the tread into different functional zones with different groove characteristics. The intermediate region is segmented with higher-frequency zigzag patterns for rolling resistance reduction, while crown and shoulder regions are segmented with lower-frequency patterns for chipping resistance, allowing each zone to optimize its performance
Data Source
AI summary
A heavy duty pneumatic tire includes a tread portion provided with circumferentially extending zigzag shaped main grooves, a plurality of land portions separated by the main grooves, and a plurality of lateral grooves to form a plurality of block elements on each land portion. Each land portion comprises a number of pitches in a range of from 40 to 50, wherein each pitch consists of one block element and one lateral groove adjacent to the concerned block element. Each block element has a length in a range of from 85% to 95% of a length of the pitch. The main grooves include a crown main groove, a shoulder main groove, and a middle main groove. The middle main groove has a zigzag amplitude larger than those of the crown main groove and the shoulder main groove.