Segmented Tire Tread with Conductive Portion for Static Discharge
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Solution Overview
Problem
Pneumatic tires with high silica content in tread rubber experience high electric resistance, leading to static charge accumulation and issues like radio noise, while conductive portions to address this often result in irregular wear and ununiformity in tread rubber.
Innovation Solution
A pneumatic tire design featuring a nonconductive cap portion and base portion with a conductive portion that extends into the tread rubber, where the cap portion has higher rubber hardness than the base portion, segmented in the tire width direction to enhance rigidity and prevent irregular wear, while maintaining conductive performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive portion is formed in the tread rubber to discharge static electricity, then the conductive performance is improved, but irregular wear is generated and uniformity is deteriorated
Solution Approach 1:
The tread rubber is divided into multiple functional segments: cap portions (nonconductive, high hardness) and base portions (nonconductive, low hardness) arranged alternately in the tire width direction. The conductive portions are strategically positioned within this segmented structure, extending from the ground surface into the tread rubber. This segmentation allows the conductive portions to maintain contact with the ground for static discharge while the surrounding cap portions provide structural support and prevent irregular wear.
Solution Approach 2:
Different regions of the tread rubber are assigned different properties: cap portions have high rubber hardness (60-80 shore A) for wear resistance and structural support, while base portions have low rubber hardness (40-60 shore A) for flexibility. The conductive portions are localized at specific positions where they can effectively discharge static electricity without compromising the overall uniformity of the tread rubber structure.
2Reliability
If the conductive portion extends closely to the ground surface to enhance conductive performance, then static charge discharge is improved, but center wear is generated due to ununiformity in rigidity
Solution Approach 1:
The alternating segmentation of hard cap portions and soft base portions creates a rigid framework that counteracts the softening effect of closely positioned conductive portions. This segmented structure ensures that even when conductive portions extend close to the ground surface for effective static discharge, the cap portions maintain the rigidity needed to prevent center wear and ensure uniform wear patterns.
Solution Approach 2:
The hard cap portions act as a counterweight to the soft base portions and conductive portions. By strategically placing high-hardness cap portions in the tire width direction, the structure compensates for the reduced rigidity caused by conductive portions extending close to the ground, thereby preventing uneven wear while maintaining effective conductive 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 effectively discharges static electricity to the road surface while inhibiting irregular wear and maintaining wear performance, ensuring uniform wear and improved steering stability.
Implementation Method 1
a conductive portion which is formed by a conductive rubber and runs into a side surface or a bottom surface of the tread rubber from the ground surface
Data Source
AI summary
A tread rubber includes a cap portion formed by a nonconductive rubber, a base portion formed by a nonconductive rubber, and a conductive portion formed by a conductive rubber. A rubber hardness of the cap portion is higher than a rubber hardness of the base portion. The base portion is segmented in a tire width direction. A rubber forming the cap portion is filled in a recess at a segmented position. The conductive portion has a first portion which is provided in an outer side of the segmented position and extends to an inner side in the tire diametrical direction from the ground surface, and a second portion which is provided continuously in the first portion and extends in the tire width direction so as to run into the side surface or the bottom surface of the tread rubber.