Small-Diameter Tire Carcass Structure for Wear and Rolling Resistance
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Solution Overview
Problem
Small-diameter tires face challenges in achieving both low rolling resistance and wear resistance performance simultaneously, as existing designs often compromise on one aspect due to structural limitations.
Innovation Solution
The tire design incorporates a carcass layer with specific organic fiber cord angles and a belt layer structure, including cross belts and a supplemental belt, to balance load capacity, wear resistance, and rolling resistance, with a tire outer diameter ranging from 200 to 660 mm and a total tire width from 100 to 400 mm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the carcass layer is strengthened to improve wear resistance and load capacity, then the tire deformation under high load is suppressed, but the rolling resistance increases due to increased carcass layer weight
Solution Approach 1:
The patent applies parameter changes by precisely controlling the tensile strength of the carcass ply within a specific range (17≤Tcs/OD≤120) and the cord angle (80≤θ≤100 degrees). This optimized parameter combination ensures the carcass layer has sufficient strength to suppress tire deformation and improve wear resistance, while avoiding excessive weight increase that would deteriorate rolling resistance performance.
2Weight of moving object
If the tire outer diameter is reduced to achieve small-diameter tire benefits, then the vehicle interior space is expanded and transportation cost is reduced, but the load capacity requirement becomes more challenging to meet
Solution Approach 1:
The patent uses parameter changes by optimizing the tensile strength parameter Tcs/OD within the range of 17 to 120, which scales with the tire outer diameter OD. This allows the carcass layer to maintain appropriate load capacity across different tire sizes while keeping the tire weight reduced. The cord angle parameter (80-100 degrees) is also optimized to enhance load-bearing efficiency in small-diameter tires.
3Reliability
If the tensile strength of the carcass ply is increased to suppress tire deformation, then the wear resistance performance is improved, but the rolling resistance deteriorates due to increased carcass layer weight
Solution Approach 1:
The patent resolves this contradiction through parameter changes by defining a specific range for the tensile strength parameter Tcs/OD (17≤Tcs/OD≤120). This range is carefully selected to provide the minimum necessary strength for suppressing tire deformation and ensuring wear resistance, while preventing excessive strength increase that would lead to unnecessary weight gain and rolling resistance deterioration. The upper limit of 120 specifically prevents over-engineering the carcass layer.
Data Source
AI summary
In a tire, a tire outer diameter OD is in a range 200 mm≤OD≤660 mm. A total tire width SW is in a range 100 mm≤SW≤400 mm. A carcass layer is formed by layering two layers of carcass plies formed by covering organic fiber cords with coating rubbers. The organic fiber cords of the two layers of the carcass plies have cord angles in a range of 80 degrees or more and 100 degrees or less with respect to a tire circumferential direction. A tensile strength Tcs per a width of 50 mm of each of the two layers of the carcass plies (13A, 13B) is in a range 17 N/mm≤Tcs/OD≤120 N/mm with respect to the tire outer diameter OD.