Small-Diameter Tire Tread Structure for Noise and Rolling Resistance
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Solution Overview
Problem
Small-diameter tires face challenges in achieving both low noise and low rolling resistance performance while maintaining load capacity, as existing designs often compromise on one or both of these aspects due to structural limitations.
Innovation Solution
The tire design incorporates a specific configuration with a pair of bead cores, a carcass layer extended across the bead cores, and a belt layer disposed radially outside the carcass layer, along with a tread portion having a groove area ratio within a defined range, which ensures appropriate load capacity, noise performance, and reduced rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the groove area ratio of the tread portion is increased to reduce noise, then noise performance is improved, but load capacity deteriorates
Solution Approach 1:
The patent optimizes the groove area ratio parameter within a specific range (0.008≤Aa/OD≤0.150) to achieve the best balance between noise reduction and load capacity. This parameter optimization allows the tire to maintain sufficient load-bearing capability while reducing noise through controlled groove geometry.
Solution Approach 2:
The patent employs a composite structure combining the carcass layer, belt layer, and tread portion with optimized groove patterns. This composite design allows different layers to work together, where the carcass and belt layers provide structural strength for load capacity while the tread portion with optimized grooves handles noise reduction, resolving the contradiction between these two requirements.
2Weight of moving object
If the tire diameter is reduced to lower transportation cost, then weight and rotational inertia are reduced, but maintaining load capacity becomes more difficult
Solution Approach 1:
The patent uses a composite structure with a carcass layer made of high-strength material and a belt layer with specific cord arrangements. This composite design compensates for the reduced diameter by using materials and structures with higher specific strength, allowing small-diameter tires to achieve adequate load capacity that would otherwise require larger dimensions.
Solution Approach 2:
The patent applies different material properties and structural characteristics to different parts of the tire. The carcass layer uses high-strength materials concentrated in critical load-bearing regions, while other areas may use lighter materials. This localized optimization allows the tire to maintain load capacity where needed while minimizing overall weight.
3Object-affected harmful factors
If the groove area ratio is optimized for noise performance, then noise is reduced, but rolling resistance may increase
Solution Approach 1:
The patent carefully adjusts the groove area ratio parameter within a narrow optimal range (0.008≤Aa/OD≤0.150) to balance noise reduction with rolling resistance. By controlling the groove dimensions, spacing, and depth parameters, the design achieves noise reduction while minimizing the increase in rolling resistance that would result from excessive groove area.
Solution Approach 2:
The patent implements a partial groove pattern rather than complete coverage, using grooves only in specific regions where they provide the most noise reduction benefit with minimal impact on rolling resistance. This selective application of groove features allows noise control without the penalty of excessive energy loss across the entire tread surface.
Data Source
AI summary
A tire includes a pair of bead cores, a carcass layer extended across the bead cores, a belt layer disposed on an outer side of the carcass layer in a radial direction, and a tread portion. A tire outer diameter OD (mm) is in a range 200≤OD≤660. A total tire width SW (mm) is in a range 100≤SW≤400. A groove area ratio Aa of the tread portion is in a range 0.008≤Aa/OD≤0.150.