Studless Tire Tread Pattern for Snow Traction and Wear Resistance

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Solution Overview

Problem

Conventional studless tires face challenges in achieving both high on-snow traction and wear resistance, as the presence of convex tie bars lowers edge pressure, leading to reduced on-snow performance and increased deformation, while relying on rubber characteristics has limitations due to rolling resistance demands.

Innovation Solution

A tread pattern featuring block rows with circumferential direction narrow grooves and wedge-shaped bent portions in the width direction grooves, which increases edge pressure and snow sharing force without tie bars, enhancing on-snow performance and wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If tie bars are used to connect land blocks, then rigidity and wear resistance are improved, but on-snow traction is lowered due to reduced edge pressure

Engineering Contradiction:
Improvewear resistanceVSAvoidedge pressure
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The patent removes the tie bar structure from the tread pattern, allowing land blocks to be independent rather than connected. This extraction of the connecting element eliminates the negative effect of tie bars on edge pressure while maintaining land block integrity through alternative means (increased land block width and optimized groove positioning).

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different groove widths at different locations: narrow grooves at the circumferential ends of land blocks and wider grooves in the middle sections. This local variation in groove geometry allows the end portions to maintain high edge pressure for on-snow traction while the middle portions provide sufficient spacing for wear distribution and flexibility.

Inventive Principle:
Principle #3Local quality

2Force

If edge pressure is increased to improve on-snow traction, then on-snow performance is improved, but land block deformation increases leading to uneven wear

Engineering Contradiction:
Improveedge pressureVSAvoidland block deformation
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The patent implements non-uniform groove widths where narrow grooves are positioned at the circumferential ends of land blocks to concentrate pressure and maintain high edge pressure for on-snow traction. The wider grooves in the middle sections allow for pressure distribution and reduce localized deformation, preventing uneven wear while maintaining high edge pressure at critical locations.

Inventive Principle:
Principle #3Local quality

3Duration of action of stationary object

If groove volume is reduced to improve wear resistance, then wear resistance is improved, but on-snow performance is lowered

Engineering Contradiction:
Improvewear resistanceVSAvoidon-snow traction
Core Design Contradiction:
Duration of action of stationary objectVSForce

Solution Approach 1:

The patent uses narrow grooves at the circumferential ends of land blocks to minimize volume reduction in critical traction areas, while wider grooves in middle sections provide sufficient snow accumulation space. This local differentiation maintains on-snow traction by preserving groove volume where needed while limiting overall volume loss to improve wear resistance.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4067116B1tire
Publication Date: 2024.05.29 BRIDGESTONE CORP
  • EP4067116B1 patent drawingFigure 1
  • EP4067116B1 patent drawingFigure 2
  • EP4067116B1 patent drawingFigure 3

AI summary

A pneumatic tire (10) has a central land region (CT1) partitioned by a pair of circumferential direction main grooves (71, 72) extending in a tire circumferential direction. In the central land region (CT1), a block row (30) partitioned by one or a plurality of circumferential direction narrow grooves (61, 62) having a groove width narrower than the circumferential direction main groove (71, 72) is provided. The block row (30) has a land block partitioned by a width direction groove extending in a tire width direction. The width direction groove includes a width direction groove portion and a bent portion continuous to the width direction groove portion and bent in the tire circumferential direction. The groove width of the bent portion along the tire width direction becomes narrower as the bent portion advances along the tire circumferential direction.