Multi-Layer Tread Structure for Tire Noise and Steering Stability
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Solution Overview
Problem
Existing tires face challenges in achieving both high-speed steering stability and noise performance, with current designs either compromising on steering stability due to soft tread lands leading to poor force transmission or increasing noise due to hard tread lands promoting vibration propagation.
Innovation Solution
A tire design featuring two or more rubber layers in the tread part, with a harder second layer and specific complex elastic modulus and groove depth ratios, along with low-density members on the inner surface, to enhance steering stability and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the tread rubber is made soft to reduce noise, then noise performance is improved, but steering stability during high-speed running deteriorates due to tread collapse during cornering
Solution Approach 1:
The tread part is divided into multiple rubber layers (first rubber layer and second rubber layer) with different properties. The first rubber layer (tread surface) is softer for noise reduction, while the second rubber layer (inner layer) is harder for structural support and steering stability, resolving the contradiction between noise performance and steering stability.
Solution Approach 2:
Different regions of the tread part have different rubber compositions and hardness. The outer first rubber layer has lower hardness for noise reduction, while the inner second rubber layer has higher hardness for maintaining steering stability during high-speed cornering, allowing each layer to optimize its local function.
2Reliability
If the tread rubber is made hard to improve steering stability, then steering stability during high-speed running is improved, but noise performance deteriorates due to vibration propagation
Solution Approach 1:
The tread part is segmented into multiple layers with the second rubber layer (inner layer) providing structural rigidity for steering stability, while the first rubber layer (outer layer) acts as a vibration-dampening interface with the road surface, reducing noise propagation to the tire interior.
Solution Approach 2:
The tread part uses a composite structure of multiple rubber layers with different hardness and damping properties. This composite material approach allows the harder second layer to provide steering stability while the softer first layer absorbs vibrations, achieving both steering stability and noise reduction simultaneously.
3Ease of manufacture
If a single-layer tread structure is used to simplify manufacturing, then manufacturing complexity is reduced, but the ability to simultaneously achieve steering stability and noise reduction is compromised
Solution Approach 1:
The tread part is divided into multiple manufacturable layers that can be produced and assembled systematically. Each layer has specific compositional requirements that can be met through standard rubber compounding and molding processes, making the multi-layer structure feasible for manufacturing while achieving superior performance.
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 design improves steering stability during high-speed running by stabilizing tread land deformation and absorbs vibrations effectively, thereby reducing noise performance.
Implementation Method 1
low-density members on the inner tire surface to absorb vibrations
Implementation Method 2
when a complex elastic modulus at 30°C of the first rubber layer is defined as E* T (MPa) and a complex elastic modulus at 30°C of the second rubber layer is defined as E* B (MPa), E* B is greater than E* T
Data Source
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AI summary
An object of the present disclosure is to provide a tire having improved total performance of steering stability during high-speed running and noise performance. Provided is a tire comprising a tread part, the tread part comprising at least a first rubber layer forming a tread surface and a second rubber layer adjacent to an inner side of the first rubber layer in a tire radial direction, wherein the tread part comprises two or more circumferential grooves extending continuously in a tire circumferential direction, a pair of shoulder land parts partitioned by the circumferential grooves and grounding ends, and a center land part located between the pair of the shoulder land parts, wherein the first rubber layer and the second rubber layer are formed of a rubber composition comprising a rubber component, wherein a ratio of a distance H2 (mm) from an outermost surface of the tread part to an outermost part of the second rubber layer to a groove depth H1 of deepest parts of the circumferential grooves (H2/H1) is 0.40 to 0.90, and wherein, when a complex elastic modulus at 30°C of the first rubber layer is defined as E*T (MPa) and a complex elastic modulus at 30°C of the second rubber layer is defined as E*B (MPa), E*B is greater than E*T, and a ratio of E*T to H2/H1 (E*T/(H2/H1)) is 6.0 or more.