Tire Tread Sipe and Groove Layout for Low SATP Cornering

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Solution Overview

Problem

Existing tire designs face a challenge in improving dry performance without increasing self-aligning torque power (SATP), as increasing tread rigidity to enhance cornering power (CP) leads to higher SATP, which is undesirable.

Innovation Solution

The tire features a tread portion with shoulder circumferential grooves, first land regions with circumferential and axial sipes, and first axial grooves that decrease rigidity, specifically designed to maintain low SATP while enhancing CP, thereby improving dry performance and wet performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the rigidity in the tire circumferential direction of the tread portion is increased, then the cornering power increases, but the self-aligning torque power increases, making it impossible to improve equivalent cornering power

Engineering Contradiction:
Improverigidity in tire circumferential directionVSAvoidself-aligning torque power
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The circumferential rigidity is segmented across different tread regions. The first land region has reduced circumferential rigidity due to axial grooves and sipes that allow circumferential deformation, reducing self-aligning torque. The middle land region maintains higher circumferential rigidity for cornering power generation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The circumferential rigidity is locally differentiated: low rigidity at the tread edge (first land region) to reduce self-aligning torque, and high rigidity in the middle land region to maintain cornering power. This local quality variation resolves the contradiction between strength and self-aligning torque power.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4070970B1tire
Publication Date: 2023.10.18 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4070970B1 patent drawingFigure 1
  • EP4070970B1 patent drawingFigure 2A~2B
  • EP4070970B1 patent drawingFigure 3

AI summary

A tire (1) includes a tread portion (2) provided with a first land region (3) demarcated between a shoulder circumferential groove (5) and a tread edge (Te). The first land region (3) is provided with first sipes (7) extending in a tire circumferential direction, axial sipes (8), and first axial grooves (9) extending from the tread edge (Te). The first sipes (7) are not connected with the first axial grooves (9). Each of the axial sipes (8) has an axially inner end connected with the shoulder circumferential groove (5). Each of the axial sipes (8) has an axially outer end connected with one of the first sipes (7).