Pneumatic Tire Central Thin Rib Sipe Design
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Solution Overview
Problem
Pneumatic tires with block arrays experience increased rolling resistance and irregular wear due to rigidity differences between blocks, which are exacerbated by segmented thin ribs and lateral grooves, leading to larger deformations and hysteresis losses.
Innovation Solution
A pneumatic tire design featuring a thin rib that continuously extends in the circumferential direction within a central area of the block array, partitioned by sipes, reduces rigidity differences and deformation, thereby minimizing rolling resistance and irregular wear by ensuring uniform slip and wear distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a thin rib is segmented by lateral grooves in the circumferential direction, then the block array rigidity decreases, but the rolling resistance increases due to larger deformation and hysteresis loss
Solution Approach 1:
The thin rib is segmented by sipes extending in the circumferential direction, creating multiple small divisions that maintain overall continuity. This segmentation allows the rib to flex slightly while maintaining structural integrity, reducing deformation without compromising rigidity significantly.
Solution Approach 2:
The sipes are positioned at specific locations within the thin rib structure, creating local variations in rigidity. The areas between sipes maintain higher rigidity while the sipe regions provide controlled flexibility, optimizing the balance between structural stability and deformation reduction.
2Strength
If a thin rib is segmented by lateral grooves, then the block rigidity within the block array decreases, but rigidity difference among blocks increases causing irregular wear
Solution Approach 1:
The continuous thin rib is divided into multiple segments by sipes, creating a series of smaller rigid units. Each segment maintains sufficient rigidity while the overall continuous structure ensures uniformity across all blocks in the circumferential direction, preventing irregular wear patterns.
Solution Approach 2:
The thin rib maintains continuous presence in the circumferential direction despite being segmented by sipes. This continuity ensures that rigidity is uniformly distributed across all blocks, preventing the rigidity differences that would otherwise cause irregular wear while still allowing controlled flexibility.
3Reliability
If blocks are partitioned by main grooves and lateral grooves, then traction performance is improved, but deformation amount increases and hysteresis loss increases
Solution Approach 1:
The thin rib with sipes is positioned in the central area of the block array to provide localized reinforcement. This local quality enhancement reduces deformation in the central region where it occurs most, lowering hysteresis loss while maintaining the groove pattern needed for traction performance.
Data Source
AI summary
An object of the present invention is to provide a pneumatic tire having low rolling resistance and higher resistance against irregular wear. To achieve the above object, a pneumatic tire includes a tread portion comprising a plurality of block arrays each of which is constituted of a plurality of blocks that are partitioned by a plurality of main grooves extending in a circumferential direction of the tire and a plurality of lateral grooves crossing the main grooves, wherein at least one of the block arrays is provided with a thin rib that continuously extends in the circumferential direction of the tire in a central area of the block array as viewed in a width direction of the tire and is partitioned by two sipes extending in the circumferential direction of the tire, the depth of the sipes extending in the circumferential direction of the tire is 0.7 times or less of the depth of the lateral grooves.