Pneumatic Tire Tread Segmentation for Drainage and Stability
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Solution Overview
Problem
Pneumatic tires with improved drainage, on-snow, and on-ice performance tend to compromise steering stability on dry road surfaces due to reduced lateral rigidity caused by longitudinal and lateral grooves and sipes.
Innovation Solution
A pneumatic tire design featuring center and shoulder longitudinal grooves, lateral grooves, and sipes that maintain lateral rigidity while enhancing drainage and traction, with specific groove and land portion configurations to balance performance across different road conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If longitudinal grooves, lateral grooves, and sipes are provided on the tread portion to improve drainage and on-ice performance, then drainage performance and on-ice performance are improved, but lateral rigidity of the tread portion is reduced, deteriorating steering stability on dry road surfaces
Solution Approach 1:
The tread portion is segmented into multiple functional zones (center land portion, outer middle land portion, inner middle land portion, outer shoulder land portion, inner shoulder land portion) with different groove configurations. Each zone is divided into blocks by longitudinal grooves, and blocks are further sectioned by lateral grooves and sipes, creating a segmented structure that provides drainage pathways while maintaining lateral rigidity through the block architecture.
Solution Approach 2:
Different regions of the tread portion are assigned different groove patterns and densities tailored to their specific functions. The center land portion has a different groove configuration compared to the shoulder land portions, allowing each region to optimize for its local requirements (steering stability at center, drainage and traction at shoulders) while contributing to overall tire performance.
2Reliability
If axially extending sipes are provided in blocks to generate friction force on icy road, then on-ice performance is improved, but lateral rigidity is further reduced, worsening steering stability
Solution Approach 1:
The sipes are implemented as transverse cuts within individual blocks rather than continuous axial grooves, segmenting the cutting edge into multiple discrete elements. This segmentation provides numerous friction-generating edges for ice traction while the block structure itself maintains lateral rigidity, resolving the contradiction between on-ice performance and steering stability.
Solution Approach 2:
Instead of using continuous axial grooves that reduce rigidity, the invention uses transverse sipes (cuts perpendicular to the axial direction) within blocks. This dimensional change allows the sipes to generate friction on ice through their edges while the block architecture in the axial direction maintains lateral rigidity, effectively decoupling the two functions.
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
The tire achieves improved drainage, on-snow, and on-ice performance while maintaining steering stability on dry road surfaces through optimized groove and land portion configurations, ensuring effective water discharge and snow shearing force, as well as high lateral rigidity.
Implementation Method 1
the longitudinal grooves and lateral grooves can smoothly discharge a water film interposed between the tire and a road surface
Implementation Method 2
the longitudinal and lateral grooves can dig into a snowy road and obtain snow column shearing force
Implementation Method 3
Edges of such sipes can generate considerable friction force on an icy road, thereby improving the on-ice performance
Data Source
AI summary
A tread portion 2 of a pneumatic tire is divided by a center longitudinal groove and a shoulder longitudinal groove into a center land portion 6, an outer middle land portion 7A, an inner middle land portion 7B, an outer shoulder land portion 8A, and an inner shoulder land portion 8B. The outer shoulder land portion 8A includes an array of outer shoulder blocks 22 which are sectioned by outer shoulder lateral grooves 5A. The inner shoulder land portion 8B includes inner shoulder lateral grooves 26 having an inner end 26i and an outer end 26o in the land portion 8B, and inner shoulder auxiliary grooves 28 disposed between the inner shoulder lateral grooves 26, 26 which are circumferentially adjacent to each other and having inner ends 28i and outer ends 28o in the land portion 8B.