Tire Bead and Sidewall Structure for Stiffness Transition Control
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Solution Overview
Problem
Existing pneumatic tire designs face challenges in achieving optimal stiffness and force direction in the transition region between the bead region and the sidewall, which affects tire performance and durability.
Innovation Solution
The design incorporates a multilayer reinforcement structure that includes a first apex, an apex extension, and a second apex, along with turnup portions of carcass plies and a chafer, to provide progressive transition from the stiff bead region to the flexible sidewall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer reinforcement structure with apex extension is added to improve stiffness in the transition region, then the tire performance and durability are improved, but the device complexity increases
Solution Approach 1:
The bead apex reinforcement is divided into multiple segments: a first apex, an apex extension, and a second apex. Each segment serves a specific function in managing stress distribution across the transition region, allowing for optimized stiffness control without requiring a completely redesign of the entire bead structure.
Solution Approach 2:
The apex extension extends in the radial direction beyond the first apex, creating a progressive transition from the bead region to the sidewall. This dimensional extension allows the reinforcement to be distributed across multiple radial positions, enhancing stiffness control while maintaining structural efficiency.
2Stability of the object's composition
If the turnup portion of the carcass ply extends along the apex extension, then the force directionality is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The turnup portion of the carcass ply is configured to extend specifically along the axially outer side of the apex extension, providing localized reinforcement where force directionality is most critical. This targeted approach enhances stability without requiring high precision across the entire tire structure.
Solution Approach 2:
The turnup portion acts as an intermediary element that bridges the bead region and the sidewall, providing a gradual transition zone. This intermediary structure helps distribute forces smoothly across the transition region, reducing the need for extremely precise positioning while maintaining force directionality.
Data Source
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AI summary
A pneumatic tire (10) is disclosed comprising a tread (12); a bead region (14): a sidewall (16); a bead core (18); a first apex (24) extending from the bead core in radially outward direction; an apex extension (26) extending in radially outward direction from the first apex, the apex extension having a radially inward end and a radially outward end; and a carcass extending along an axially inner side of the sidewall to the bead region. The carcass includes a first ply (20) turned up around the bead core from an axially inner side to an axially outer side of the bead core so as to form a first turnup portion (20a), the first turnup portion extending along an axially outer side of the first apex and along an axially outer side of the apex extension and terminating radially inwardly from the radially outward end of the apex extension, and a second ply (22) turned up, between the bead core and the first ply, around the bead core from an axially inner side to an axially outer side of the bead core so as to form a second turnup portion (22a), the second turnup portion extending along the axially outer side of the first apex (24). A chafer (30) is positioned around a portion of the bead core and the first and second turnup portions, the chafer comprising a toe guard (36) and a rim flange protector (40), and a second apex (42) is positioned between the rim flange protector (40) and at least one of the first apex (24) and the apex extension (26).