Off-Road Motorcycle Tire Shoulder Block Rigidity via Bead Apex Extension
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Solution Overview
Problem
Existing motorcycle tires for rough terrain face insufficient shoulder block rigidity during jumping and cornering in off-road competitions, which compromises cornering performance, and introducing narrow grooves to enhance lateral grip reduces shoulder block rigidity further.
Innovation Solution
The tire design includes rows of shoulder blocks and middle blocks with narrow circumferential grooves, extended bead apex rubbers, and a specific carcass structure with increased carcass cords and plies to enhance shoulder block rigidity and lateral grip while maintaining shock absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If narrow grooves are introduced in the shoulder block to increase lateral grip force, then lateral grip force is improved, but the rigidity of the shoulder block is decreased
Solution Approach 1:
The patent applies different groove patterns to different regions of the tread. Narrow grooves are introduced only in the middle blocks and center blocks, while the shoulder blocks maintain a solid structure without grooves. This local differentiation allows the middle and center regions to provide lateral grip through groove interlocking, while the shoulder blocks maintain rigidity for cornering support.
Solution Approach 2:
The tread is segmented into distinct functional zones: shoulder blocks for rigidity and cornering support, middle blocks for lateral grip with narrow grooves, and center blocks for traction. This segmentation allows each region to optimize its performance characteristics without compromising the overall tire performance.
2Strength
If the bead apex extends to the root portion of the shoulder block to reinforce the sidewall, then side rigidity is increased, but the complexity of the tire structure increases
Solution Approach 1:
The bead apex is merged with the shoulder block structure, where the bead apex extends radially outward to reach the root portion of the shoulder block. This integration creates a unified structural element that simultaneously provides sidewall reinforcement and shoulder block support, reducing the need for separate reinforcement components.
Data Source
AI summary
A tire comprises shoulder blocks and middle blocks having ground contacting surfaces respectively provided with narrow grooves and each including a circumferential groove portion. The tire further comprises bead apex rubbers each extending from respective one of bead cores and each of the bead apex rubbers includes an extended portion extending to a position on an inner side in a tire axial direction of a first reference line passing through the circumferential groove portion of each of the shoulder blocks.