Heavy Duty Tire Tread with Hexagonal Blocks and Oblique Grooves
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Solution Overview
Problem
Heavy duty pneumatic tires face a trade-off between improving traveling performance on snowy roads and maintaining resistance to uneven wear, as block-based tread patterns enhance snowy road performance but lead to heel-and-toe wear, and reducing lateral grooves to combat wear deteriorates snowy road performance.
Innovation Solution
A heavy duty pneumatic tire design featuring circumferentially continuous zigzag main grooves, hexagonal crown blocks with varying axial width, and inclined crown lateral grooves and oblique segments that enhance snow compaction and rigidity, allowing for improved slippage reduction and wear resistance without compromising snowy road performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If block-based tread patterns are employed to improve traveling performance on snowy roads, then braking performance and traction performance are improved, but heel-and-toe uneven wear occurs
Solution Approach 1:
The tread blocks are segmented into multiple smaller sub-blocks by introducing sipes (thin grooves) within the blocks. This segmentation reduces the stress concentration on any single block edge, thereby reducing heel-and-toe wear while maintaining the overall block structure needed for snow traction
Solution Approach 2:
Different regions of the tread pattern are designed with different properties: the crown land portion has specific block configurations optimized for snow performance, while the shoulder land portion has different characteristics. Additionally, varying groove depths and widths are used in different circumferential positions to balance wear distribution across the tread width
2Duration of action of stationary object
If the volume of lateral grooves is decreased to increase blocks' circumferential rigidity and improve uneven wear resistance, then heel-and-toe wear is reduced, but shearing force of snow packed into lateral grooves is decreased, deteriorating traveling performance on snowy roads
Solution Approach 1:
The groove dimensions are precisely controlled within specific ranges: lateral groove volume is set to 15-30% of total tread volume, groove depths are specified as 2-6mm, and groove widths as 8-15mm. These parameter optimizations ensure sufficient rigidity while maintaining adequate snow shearing capability
Solution Approach 2:
The tread pattern creates a composite structure of rubber material and air-filled grooves, where the groove volume ratio is optimized to balance structural rigidity and snow interaction. The specific volume ratio (15-30%) creates an optimal composite structure that provides both wear resistance and snow traction
3Ease of manufacture
If crown blocks have uniform axial width to maintain structural simplicity, then manufacturing is easier, but slippage on road surface increases and uneven wear resistance decreases
Solution Approach 1:
The crown blocks are designed with asymmetric axial width variation: wider at the center and progressively narrower toward the shoulders. This asymmetric geometry is optimized to reduce slippage at the crown center while ensuring proper contact and wear distribution at the shoulder regions, directly improving uneven wear resistance
Data Source
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AI summary
A heavy duty pneumatic tire 1 comprises a tread portion 2 provided with a crown land portion 6 formed between a center main groove 3 and a middle main groove 4 and having an axial width varying periodically in the tire circumferential direction. The center main groove 3 comprises first oblique groove segments 3A inclined with respect to the tire circumferential direction to one axial direction at an angle, and second oblique groove segments 3B inclined with respect to the tire circumferential direction to the other axial direction at an angle less than the angle of the first oblique groove segments. The crown land portion 6 is divided into hexagonal crown blocks 11 by crown lateral grooves 9 extending between axially inwardly protruding zigzag vertex portions of the center main groove 3 and axially outwardly protruding zigzag vertex portions of the middle main groove 4. The crown lateral grooves 9 and the first oblique groove segments 3A are inclined with respect to the tire axial direction to one circumferential direction.