Pneumatic Tire Bead Area Rubber Layer Design
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Solution Overview
Problem
Current pneumatic vehicle tires face challenges in durability, particularly in the bead area where stress concentrations and direct contact between reinforcement layers lead to reduced tire longevity.
Innovation Solution
A rubber layer with a consistent thickness is introduced between the carcass and additional reinforcement layers, tapering triangularly at the bead area to prevent kinking and force peaks, reducing shear stress and enhancing layer transition, with specific thicknesses and orientations optimizing the coupling between carcass and bead reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the additional reinforcement layer is arranged axially on the outside of the carcass to strengthen the sidewall, then the tire gains runflat properties and improved durability, but direct contact between the carcass and additional reinforcement layer causes chafing and reduces tire longevity
Solution Approach 1:
A rubber layer is introduced as an intermediary element between the carcass and the additional reinforcement layer. This rubber layer prevents direct contact and chafing between the reinforcement members of the carcass ply and the additional reinforcement ply, while still allowing the additional reinforcement layer to provide structural support and runflat properties. The rubber layer acts as a protective mediator that eliminates the harmful friction and wear between the two reinforcement layers.
2Stability of the object's composition
If the rubber layer thickness varies in the bead area to accommodate layer transitions, then the layers can be staggered, but kinks and force peaks occur in the bead area reducing durability
Solution Approach 1:
The rubber layer is designed with non-uniform thickness distribution, featuring a first thickness in the bead area and a second thickness in the crown area. This local quality variation allows the rubber layer to accommodate the transition between the carcass and additional reinforcement layer at different locations, creating a harmonious staggered arrangement that avoids kinks and force peaks while maintaining bead area durability.
Data Source
Figure 1
AI summary
Vehicle pneumatic tire with belt plies (2a, 2b), with two sidewalls, with two bead areas (5) each with at least one bead core (7), with a carcass (3) which runs through the tire from bead area (5) to bead area (5), wraps around the bead areas (5) from axially inside to axially outside and ends as a carcass high-profile edge at a height D, wherein D is arranged radially outside with respect to the bead area, with an additional reinforcing layer (9) having a reinforcing element, which is arranged axially outside on the carcass (3) and in the sidewall (6) such that its lower end (10) is at the level of the bead area (5) and its upper end (11) is below a belt ply (2a, 2b) and with a rubber layer (15) which is arranged between the carcass (3) and the additional reinforcing layer (9).This rubber layer (15) has a uniform thickness along its radial extent, but at its lower end (16) facing the bead area – viewed in the tire cross-section – it tapers triangularly from a height B and terminates in a point (19), so that at height B the thickness of the rubber layer (15) is greater than the thickness of the axially outside carcass high edge (3a), with B being at the height of the upper end of the bead area and this lower end (16) of the rubber layer being arranged axially inside with respect to the bead area (5).