Tire Bead Apex Geometry for Low Rolling Resistance and Braking
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Solution Overview
Problem
Tires face a challenge in reducing rolling resistance while maintaining braking performance and steering stability, as simplifying the tire structure alone is insufficient to meet the required reduction in rolling resistance.
Innovation Solution
A tire design with specific geometrical parameters, including a bead apex configuration and tire mold contours, is implemented to control deflection, enhance braking performance, and reduce rolling resistance while ensuring necessary steering stability, featuring a tread, sidewalls, beads, and a carcass structure optimized for a speed range of 270 km/h to 300 km/h.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the tire structure is simplified to reduce rolling resistance, then rolling resistance is reduced, but braking performance and steering stability deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the bead apex geometry parameters (height ratio of 20-30% and angle of 45-55 degrees) to achieve optimal balance between rolling resistance reduction and braking performance maintenance. This quantitative parameter optimization allows the tire to exhibit appropriate deflection characteristics that simultaneously reduce energy loss and maintain reliability.
Solution Approach 2:
The patent applies local quality by optimizing specific regions of the tire structure, particularly the bead apex area, with precise geometric parameters. The localized control of apex height and angle creates specific deflection characteristics in the bead region that contribute to overall tire performance, allowing different parts of the tire to have differentiated functions for reducing rolling resistance while maintaining braking performance.
2Loss of energy
If the tire structure is simplified to reduce rolling resistance, then rolling resistance is reduced, but steering stability deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the bead apex geometry parameters (height ratio of 20-30% and angle of 45-55 degrees) to achieve optimal balance between rolling resistance reduction and steering stability maintenance. This quantitative parameter optimization allows the tire to exhibit appropriate deflection characteristics that simultaneously reduce energy loss and maintain stability.
3Reliability
If the bead apex height is increased to enhance braking performance, then braking performance is improved, but rolling resistance increases
Solution Approach 1:
The patent applies parameter changes by optimizing the bead apex height ratio to a specific range (20-30% of tire cross-sectional height). This controlled parameter adjustment ensures that the apex is tall enough to provide adequate braking performance through appropriate deflection, yet not so tall as to increase rolling resistance excessively.
Solution Approach 2:
The patent applies local quality by optimizing the specific geometry of the bead apex region with controlled height and angle parameters. This localized structural optimization creates specific mechanical properties in the bead area that contribute to braking performance without adversely affecting overall rolling resistance.
Data Source
AI summary
A tire includes a tread, a pair of sidewalls, a pair of beads, and a carcass. Each bead includes a core and an apex. In the tire in the normal state, a ratio (HA/HS) of a distance HA in a radial direction from a bead base line to an outer end PA of the apex to a tire cross-sectional height HS may not be less than 20% and/or may not be greater than 30%, and an angle of a line segment connecting between the outer end PA of the apex and a center PM of a width, in an axial direction, of a contact surface of the apex at which the apex is in contact with the core, relative to the bead base line, may not be less than 45° and/or may not be greater than 55°.