Tire Tread Sipe Angles for Snow Grip and Dry Stability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Tires designed for snowy and icy roads often compromise steering stability on dry surfaces due to increased sipe numbers, which reduce stiffness and affect performance.

Innovation Solution

A tire design featuring a shoulder land portion, a middle land portion, and a circumferential narrow groove with angled sipes and grooves that support each other to maintain stiffness on dry roads while enhancing traction on icy surfaces through strategically placed sipes and grooves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of sipes is increased to improve on-snowy and icy road performance, then frictional force on snowy and icy roads is increased, but the stiffness of the land portion decreases leading to deterioration in steering stability on dry road surfaces

Engineering Contradiction:
Improveon-snowy and icy road performanceVSAvoidsteering stability on dry road surfaces
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by differentiating sipe configurations between shoulder land portions and middle land portions. Shoulder sipes have inner inclined portions with angle β greater than the angle α of middle sipes, creating locally optimized friction characteristics at the shoulder region for snowy/icy roads while preserving land portion stiffness through the circumferential narrow groove.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the sipe structure into distinct components: shoulder sipes with inner inclined portions, middle sipes, and circumferential narrow grooves. This segmentation allows independent optimization of each component's function while maintaining overall structural integrity and stiffness.

Inventive Principle:
Principle #1Segmentation

2Reliability

If sipes are made with narrow width to increase frictional force on snowy and icy roads, then on-snowy and icy road performance is improved, but the land portion stiffness is reduced

Engineering Contradiction:
Improvefrictional force on snowy and icy roadsVSAvoidland portion stiffness
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent creates local quality differences by providing shoulder sipes with inclined portions at the shoulder land portion where high friction is needed, while maintaining a circumferential narrow groove that preserves the stiffness of the middle land portion. The angle β of inner inclined portions is specifically greater than angle α of middle sipes, optimizing local friction characteristics.

Inventive Principle:
Principle #3Local quality

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 on-snowy and icy road performance while maintaining steering stability on dry surfaces, preventing stiffness reduction and ensuring high uneven wear resistance.

Implementation Method 1

Such tires exert increased frictional force on snowy and icy road surfaces due to the edges of the sipes

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3378678B1tire
Publication Date: 2021.01.20 SUMITOMO RUBBER INDUSTRIES LTD
  • EP3378678B1 patent drawingFigure 1
  • EP3378678B1 patent drawingFigure 2
  • EP3378678B1 patent drawingFigure 3

AI summary

The object of the present invention is to improve on-snowy and icy road performance while maintaining steering stability on dry road surfaces. Provided is a tire (1) in which a shoulder land portion (3), a middle land portion (4), and a circumferential narrow groove (10) provided between the middle land portion (4) and the shoulder land portion (3) and extending in a tire circumferential direction are provided in a tread portion (2). A plurality of middle sipes (11) having an angle α relative to a tire axial direction are provided in the middle land portion (4). A plurality of shoulder sipes (13) are provided in the shoulder land portion (3). The plurality of shoulder sipes (13) each have an inner inclined portion (15) provided closer to the circumferential narrow groove (10) and inclined relative to the tire axial direction at an angle β greater than the angle α of the middle sipe (11).