Tire Tread Narrow Groove Structure to Suppress Cut Separation

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Solution Overview

Problem

Narrow groove widths in tire treads lead to increased separation between the tread rubber and the belt due to cuts from the road surface, which reduces the total life of the tire without sufficient wear life improvement.

Innovation Solution

A tire design with specific groove configurations, including center-side and shoulder-side narrow grooves with varying widths and shapes, that absorb crushing deformation and suppress shear strain, maintaining wear life while preventing cut separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a tire has high rigidity to suppress vibration and provide stable steering, then steering stability is improved, but impact resistance deteriorates causing discomfort on rough roads

Engineering Contradiction:
Improvesteering stabilityVSAvoidimpact resistance
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The tire's reinforcement structure is segmented into multiple independent elements (first and second reinforcement elements) with different orientations. The first reinforcement elements are arranged radially to suppress radial vibrations, while the second reinforcement elements are arranged at oblique angles to suppress circumferential vibrations and improve impact resistance. This segmentation allows each element to specialize in suppressing specific vibration modes without compromising overall steering stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the tire bead reinforcement structure have different element arrangements optimized for local requirements. The first reinforcement elements provide high rigidity in the radial direction where steering stability is critical, while the second reinforcement elements provide enhanced flexibility in circumferential directions where impact absorption is needed. This local differentiation of structural properties resolves the contradiction between steering stability and impact resistance.

Inventive Principle:
Principle #3Local quality

2Device complexity

If a tire uses uniform reinforcement elements to simplify structure, then manufacturing is easier, but vibration suppression in specific directions deteriorates

Engineering Contradiction:
Improvestructure complexityVSAvoidvibration suppression
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The reinforcement structure is divided into functionally distinct segments: first reinforcement elements with radial arrangement for primary structural support, and second reinforcement elements with oblique arrangement for targeted vibration suppression. This segmentation creates a modular structure that is easier to manufacture than fully customized designs while achieving superior directional vibration suppression compared to uniform structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reinforcement elements are arranged asymmetrically with respect to the tire's radial and circumferential directions. The first elements are symmetrically arranged radially, while the second elements are arranged at specific oblique angles (e.g., 45 degrees) to target specific vibration modes. This asymmetric arrangement optimizes vibration suppression in critical directions without requiring complete structural complexity.

Inventive Principle:
Principle #4Asymmetry

3Productivity

If a tire has high rigidity to maintain shape and reduce rolling resistance, then fuel efficiency is improved, but comfort on rough roads deteriorates

Engineering Contradiction:
Improvefuel efficiencyVSAvoidroad comfort
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The bead reinforcement structure is segmented into elements with different orientations that independently address different performance requirements. The radially arranged first elements maintain tire shape and reduce rolling resistance for fuel efficiency, while the obliquely arranged second elements provide flexibility for comfort on rough roads. This segmentation allows simultaneous optimization of both fuel efficiency and road comfort.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the structural parameters of the reinforcement elements by varying their arrangement angles and positions. By adjusting the angle of the second reinforcement elements relative to the radial direction, the tire can optimize the balance between rigidity (for fuel efficiency) and flexibility (for comfort). This parameter optimization allows the tire to maintain shape for low rolling resistance while absorbing road irregularities for comfort.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4427945B1tire
Publication Date: 2026.04.08 BRIDGESTONE CORP
  • EP4427945B1 patent drawingFigure 1
  • EP4427945B1 patent drawingFigure 2A~2B
  • EP4427945B1 patent drawingFigure 3

AI summary

The tire 10 comprises a widthwise narrow groove 8 extending with a tire widthwise component on a tread surface 11. The widthwise narrow groove 8 has a center-side narrow groove portion 8a located on the inner side in the tire width direction and a shoulder-side narrow groove portion 8b connected to the outer side of the center-side narrow groove portion 8a in the tire width direction, the center-side narrow groove portion 8a is formed, from groove opening side to groove bottom side, in a shape of a continuous series of: a narrow section 8au including the groove opening; a tapered section 8at where the groove width increases toward the groove bottom; a wide straight section 8as extending in the groove depth direction with a constant groove width and having a groove width greater than that of the narrow section; and an arc-shaped section 8ab including the groove bottom, and the shoulder-side narrow groove portion 8b is formed, from groove opening side to groove bottom side, in a shape of a continuous series of: a narrow section 8bu including the groove opening; a tapered section 8bt where the groove width increases toward the groove bottom; and an arc-shaped section 8bb including the groove bottom.