Pneumatic Tire Ply Venting Layout for Hollow Portion Air Control
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Solution Overview
Problem
Air entry into the hollow portion of a pneumatic tire with a carcass ply can occur, leading to potential air retention and affecting tire performance.
Innovation Solution
A pneumatic tire design featuring a first ply with higher density ventilation holes in the central portion and no ventilation holes in the side portions, combined with a discontinuous second ply having a hollow portion, to effectively disperse and prevent air entry through bleeder cords and strategically placed ventilation holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a discontinuous second ply with a hollow portion is used, then weight is reduced and rolling resistance is decreased, but air entry into the hollow portion may occur
Solution Approach 1:
The first ply is segmented into multiple regions with different ventilation hole densities: a high-density region above the hollow portion, medium-density regions at the shoulders, and low-density or no-hole regions at the sidewalls. This segmentation allows targeted air discharge where needed while maintaining structural integrity where not needed.
Solution Approach 2:
Different regions of the first ply are given different local qualities in terms of ventilation hole density. The central region directly above the hollow portion has the highest density to prevent air entry, while sidewall regions have lower density or no holes to maintain strength. This local differentiation resolves the contradiction between air entry prevention and weight reduction.
2Reliability
If ventilation holes are formed in the first ply, then air entry is suppressed, but rigidity of the sidewall portion may be reduced
Solution Approach 1:
The first ply has non-uniform ventilation hole density distributed across different regions. The high-density region is localized directly above the hollow portion where air entry is most likely, while the sidewall regions have zero or low density to preserve rigidity. This spatially differentiated approach resolves the contradiction between air suppression and strength maintenance.
Solution Approach 2:
The first ply is divided into functional zones with different ventilation characteristics: a central high-density zone for air discharge, shoulder zones with medium density, and sidewall zones with low or zero density. This segmentation allows the structure to achieve air entry suppression where critical while maintaining strength where required.
3Reliability
If ventilation holes are distributed uniformly, then air discharge is facilitated, but local air concentration cannot be prevented
Solution Approach 1:
Instead of uniform distribution, the invention implements non-uniform ventilation hole density tailored to local air entry risks. The highest density is placed directly above the hollow portion where air tends to concentrate, with progressively lower density toward the sidewalls. This targeted approach prevents local air concentration while facilitating overall discharge.
Data Source
AI summary
A pneumatic tire includes a tread portion, a pair of sidewall portions, a first ply, and a discontinuous second ply composed of a pair of ply pieces. The first ply has a central portion and a pair of first side portions extending from both ends of the central portion to the inner side in the tire radial direction. Each of the ply pieces has an inner end portion disposed on the outer side in the tire radial direction of the central portion and a second side portion extending from the inner end portion to the inner side in the tire radial direction. The first ply is provided with a plurality of ventilation holes, and the density of the ventilation holes in the central portion is higher than the density of the ventilation holes in the pair of first side portions.