Bead-Reinforced Pneumatic Tire Shape for Low High-Speed Rolling Resistance
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Solution Overview
Problem
Conventional pneumatic tires do not adequately reduce rolling resistance during high-speed running and lack sufficient durability.
Innovation Solution
A pneumatic tire design featuring a bead reinforcing layer outside the carcass, with specific tire shape parameters (1963.4 ≦ Dt² × π / Wt ≦ 2827.4 and (V + 1.5 × 10⁷) / Wt ≦ 2.88 × 10⁵) and optimized rubber compositions to enhance durability and reduce rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional rubber composition formulation is used to reduce rolling resistance, then fuel efficiency is improved, but rolling resistance during high-speed running is not sufficiently reduced and durability is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the tire's geometric parameters (outer diameter Dt, cross-sectional width Wt, and virtual volume V) to satisfy specific mathematical relationships. This resolves the contradiction by optimizing the tire shape parameters to reduce rolling resistance during high-speed running while maintaining durability, moving beyond conventional rubber composition formulation alone.
Solution Approach 2:
The patent uses composite materials by combining the carcass layer with a bead reinforcing layer having different material properties. The bead reinforcing layer is positioned on the outer side of the carcass in the tire axial direction, creating a composite structure that simultaneously improves fuel efficiency and durability through the synergistic effects of different materials.
2Reliability
If a bead reinforcing layer is added outside the carcass, then durability is improved, but tire structure complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the tire structure into distinct functional layers: the carcass layer and the bead reinforcing layer positioned outside it. This segmentation allows each layer to perform its specific function independently, improving durability while keeping the structural complexity manageable through clear functional division.
Solution Approach 2:
The patent applies dimensionality change by positioning the bead reinforcing layer on the outer side of the carcass in the tire axial direction, rather than only in the radial direction. This spatial arrangement in multiple dimensions optimizes the reinforcement effect while maintaining a relatively simple overall structure.
3Use of energy by moving object
If tire shape parameters are optimized to reduce rolling resistance, then fuel efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges and relationships (Dt, Wt, V satisfying the given formulas) that provide a manufacturing window. By specifying ranges rather than exact values, the patent balances fuel efficiency improvement with manufacturability, reducing the stringency of precision requirements while still achieving the desired performance.
Data Source
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AI summary
A pneumatic tire is provided which has sufficiently reduced rolling resistance during high-speed running and which has excellent durability. The pneumatic tire has a bead portion, carcass and tread, wherein: a bead-reinforcing layer that reinforces the bead portion from outside of the carcass is provided outside of the carcass in the tire axis direction; and the pneumatic tire satisfies (formula1) and (formula 2) below, where Wt (mm) is the cross-sectional width of the tire when the tire installed on a standardized rim and the internal pressure is 250 kPa, Dt (mm) is the outer diameter, and the virtual volume V(mm3) is the volume of the space occupied by the tire. 1600≦Dt2×π/4/Wt≦2827.4 V+1.5×107/Wt≦2.88×105