Single-Carcass Pneumatic Tire Structure for Rigidity and Burst Resistance
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Solution Overview
Problem
Reducing the number of carcass layers in a tire to minimize weight while maintaining high-speed durability, steering stability, and shock burst resistance is challenging, as it often results in insufficient lateral rigidity and reduced shock burst resistance.
Innovation Solution
A pneumatic tire design with a single carcass layer, utilizing organic fiber cords with specific elongation ratios and fineness, combined with a unique under tread rubber composition and belt reinforcing layer, to achieve balanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the number of carcass layers is reduced to one layer for weight reduction, then the weight of the tire is reduced, but the lateral rigidity becomes insufficient and high-speed steering stability cannot be obtained
Solution Approach 1:
The patent changes the parameters of the carcass cord by specifying precise ranges for elongation ratio under load (5.5%-8.5%) and elongation at break (20%-30%), and controls the product A=D×Ec within 1.8-105 dtex/50 mm to 3.0×105 dtex/50 mm. These parameter optimizations enable a single-layer carcass to achieve both weight reduction and sufficient lateral rigidity for high-speed steering stability.
Solution Approach 2:
The patent employs composite material design by combining organic fiber cords with specific elastomeric compositions in the under tread layer. The under tread rubber composition contains specific components including polybutadiene rubber (30-70 parts by mass), polysulfide rubber (10-40 parts by mass), and various fillers, creating a composite structure that enhances the performance of the single-layer carcass.
2Weight of moving object
If the number of carcass layers is reduced to one layer, then the weight of the tire is reduced, but the shock burst resistance is lowered
Solution Approach 1:
The patent optimizes the elongation at break of the carcass cord within 20%-30% and controls the product A=D×Ec to achieve optimal shock absorption characteristics. This parameter optimization allows the single-layer carcass to sufficiently allow deformation during plunger energy tests, improving breaking energy and shock burst resistance.
Solution Approach 2:
The under tread layer uses a composite rubber composition containing polybutadiene rubber, polysulfide rubber, specific fillers (carbon black, silica), and anti-aging agents. This composite material design enhances the shock burst resistance of the single-layer carcass structure.
3Strength
If the fineness of the carcass cord is thickened to ensure the same level of performance as the conventional two-layer structure, then the performance is improved, but heat build-up is deteriorated and high-speed durability cannot be ensured
Solution Approach 1:
The patent precisely controls the fineness parameter A=D×Ec within specific ranges (1.8-105 dtex/50 mm to 3.0×105 dtex/50 mm) and optimizes the elongation ratio under load to 5.5%-8.5%. These parameter changes enable the carcass cord to provide sufficient strength while maintaining low heat build-up, ensuring high-speed durability.
Data Source
AI summary
In a pneumatic tire including one carcass layer and a tread portion comprising a cap tread layer and an under tread layer, the under tread layer comprises a rubber composition having hardness at 20° C. of 60 to 65, tensile stress at 100% elongation at 100° C. of 2.0 MPa to 4.0 MPa, and a product of tensile strength at 100° C. and an elongation at break at 100° C. of 2000 or more, the carcass layer comprises an organic fiber cord having an elongation ratio under a load of 1.5 cN/dtex on a belt layer inner circumferential side of 5.5% to 8.5% and an elongation at break of 20% to 30%, and a product A=D×Ec of a fineness based on corrected mass D per carcass cord and an insertion count Ec is from 1.8×105 dtex/50 mm to 3.0×105 dtex/50 mm.