Tyre Tread Block Lateral Covering for Grip and Wear

Solution Overview

Problem

Existing snow tires face a trade-off between improved grip on ice-covered and snow-covered surfaces and durability, as reducing stiffness to enhance grip often leads to increased wear.

Innovation Solution

A tread band with blocks featuring a main sipe and secondary sipes, where each lateral face is covered with a material having a higher modulus of elasticity than the rubber-like material, and incorporating expanded portions for enhanced water discharge and grip, while maintaining durability through a combination of low modulus rubber and a network of sipes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the stiffness of the block is reduced by using rubber-like material with low modulus of elasticity, then the grip on snow-covered ground is improved, but the wear of the block increases dramatically

Engineering Contradiction:

Improvegrip on snow-covered groundVSAvoiddurability of block

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies local quality by differentiating the properties of different parts of the block. The contact face uses soft rubber-like material for grip, while the lateral faces are covered with harder covering material (modulus of elasticity greater than the rubber-like material) to reduce wear. This allows each part to have the optimal property for its specific function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining rubber-like material with covering material on the lateral faces. The covering material has a higher modulus of elasticity than the rubber-like material, creating a composite structure that provides both the low stiffness needed for grip and the high stiffness needed to reduce wear.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the stiffness of the block is reduced to improve grip on ice-covered ground, then the speed acceleration performance and braking performance are improved, but the durability of the tyre decreases

Engineering Contradiction:

Improvegrip on ice-covered groundVSAvoiddurability of tyre

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies local quality by differentiating the properties of different parts of the block. The contact face uses soft rubber-like material for grip, while the lateral faces are covered with harder covering material (modulus of elasticity greater than the rubber-like material) to reduce wear. This allows each part to have the optimal property for its specific function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining rubber-like material with covering material on the lateral faces. The covering material has a higher modulus of elasticity than the rubber-like material, creating a composite structure that provides both the low stiffness needed for grip and the high stiffness needed to reduce wear.

Inventive Principle:

Principle #40Composite materials

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 solution improves the rigidity of the blocks, maintaining durability while enhancing water discharge and grip on ice-covered surfaces, with the covering material's high dynamic shear modulus and optional fiber or thermoplastic composition further improving performance.

Implementation Method 1

The covering material has a modulus of elasticity which is greater than the modulus of elasticity of the rubber-like material forming the block

Methodology Applied

Scientific EffectModulus of elasticity: Elasticity

Implementation Method 2

the combination of a rubber-like material having a low modulus of elasticity with a network of main sipe and secondary sipes is possible, without decreasing so much the durability of this tyre. Indeed with the expanded portion, we improve the water discharging effect making better the grip on ice-covered ground.

Methodology Applied

Scientific EffectWater discharge effect:

Data Source

PatentEP3099516B1Tread band comprising blocks with layers of covering material on their lateral surfaces

Publication Date: 2019.09.04 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

Figure 1~2
Figure 3~4

AI summary

Tread band made of rubber-like material for a tyre. The tread band comprises a plurality of blocks (3), each block (3) having a contact face (5) designed to come into contact with the ground when the tyre travels and a plurality of lateral faces (7). Each block (3) comprises a main sipe (9) extending along a main direction. Each block (3) comprises a plurality of secondary sipes (13) perpendicular to the main sipe (9). Each lateral face (7) of the block (3) is covered by a layer (15) of covering material over at least 50% of the surface of this lateral face (7). The covering material has a modulus of elasticity which is greater than the modulus of elasticity of the rubber-like material forming the block (3). The main sipe (9) and/or each secondary sipe (13) has/have an expanded portion (17) in the depth of the block (3).