Heavy Duty Tire Tread Land Zone Rigidity and Wear
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Solution Overview
Problem
Heavy duty tires experience uneven wear, particularly heel-and-toe wear, due to insufficient rigidity in the crown and middle land zones, which affects their performance during cornering and wet conditions.
Innovation Solution
The tire design incorporates a tread pattern with main grooves, land zones, sipes, and shallow grooves, where sipes intersect with shallow grooves, and the first and second recesses enhance the rigidity of the land zones, reducing uneven wear without compromising wet performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shallow grooves are provided in the crown land zone and middle land zones to improve wet performance, then wet performance is improved, but heel-and-toe wear occurs due to insufficient rigidity
Solution Approach 1:
The land zones are segmented into multiple regions: crown land zone, middle land zones, and shoulder land zones. Each zone is further divided into first land zones (with sipes and shallow grooves) and second land zones (without sipes or grooves). This segmentation allows different regions to have different functions - some areas provide drainage while others maintain rigidity to prevent heel-and-toe wear.
Solution Approach 2:
Different portions of the tread are given different structural qualities. The crown land zone and middle land zones contain sipes and shallow grooves for wet performance, while the shoulder land zones are kept solid to maintain rigidity. Additionally, within the first land zones, sipes have greater depth than shallow grooves to create localized rigidity variations that prevent uneven wear while maintaining drainage capability.
2Reliability
If sipes with deep depth are provided to improve wet performance, then wet performance is improved, but uneven wear occurs at the ends of shallow grooves
Solution Approach 1:
Instead of providing uniform deep grooves across all land zones, the invention applies deep sipes only in specific first land zones while leaving other areas with shallower grooves or no grooves. This partial application of deep cutting structures prevents excessive wear at groove ends while maintaining adequate wet performance in the regions where sipes are provided.
Solution Approach 2:
The invention varies the depth parameter of groove structures across different land zones and within the same land zone. Sipes have greater depth than shallow grooves, and the depth of both varies by location (crown vs. middle vs. shoulder land zones). This parameter variation optimizes both wet performance and wear uniformity by matching groove depth to the specific functional requirements of each region.
Data Source
AI summary
A heavy duty tire comprises a tread portion provided with annular land zones divided by circumferentially extending main grooves. At least one of the land zones is provided with first recesses disposed at one edge of the first land zone, second recesses disposed at the other edge of the first land zone, sipes extending from the first recesses to the second recesses, and shallow grooves extending from non-recessed portions of one edge of the first land zone to non-recessed portions of the other edge. The depth of the shallow grooves is less than the depth of the sipes.