Pneumatic Tire Reinforcement Sheet Tip-Sharpening
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Solution Overview
Problem
Pneumatic tires using thermoplastic resin or thermoplastic resin compositions as inner liner layers or reinforcement sheets often experience cracking and peeling at the end portions in the tire's circumferential direction, leading to reduced durability.
Innovation Solution
A pneumatic tire design where the sheet end portions extending in the tire's circumferential direction are subjected to a tip-sharpening process, with specific thickness and length criteria, to enhance stress distribution and prevent cracking and peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a sheet-shaped material made of thermoplastic resin or thermoplastic resin composition is used as an inner liner layer or reinforcement sheet, then the tire can be manufactured with streamlined processes and improved manufacturing efficiency, but cracking and peeling occur at the end portions of the sheet after the tire starts running, reducing durability
Solution Approach 1:
The patent applies local quality by subjecting only the end portions of the sheet to the tip-sharpening process, while the central portion remains unchanged. This localized treatment creates a gradient structure where the sharpened end portions have improved stress distribution characteristics, preventing cracking and peeling, while the rest of the sheet maintains its original properties for manufacturing efficiency
Solution Approach 2:
The tip-sharpening process is applied in advance during sheet preparation, before the sheet is incorporated into the tire. This preliminary action pre-treats the vulnerable end portions to prevent future cracking and peeling, addressing the durability issue before the tire starts running
2Reliability
If the sheet end portions are subjected to tip-sharpening process with specific thickness reduction, then cracking and peeling are prevented improving durability, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies parameter changes by modifying the thickness parameter of the sheet at its end portions through the tip-sharpening process. The thickness is reduced to satisfy the relation 0.1t≤T≤0.8t at a position shifted inward by (t×1/3) from the tip, where t is the average thickness. This parameter modification improves stress distribution and prevents cracking, while the process can be integrated into existing manufacturing equipment
Data Source
AI summary
The present invention provides a pneumatic tire using a sheet-shaped material made of a thermoplastic resin or a thermoplastic resin composition obtained by blending a thermoplastic resin with an elastomer as an inner liner layer or a reinforcement sheet for reinforcing a certain part of the pneumatic tire, the pneumatic tire being capable of suppressing occurrence of cracking or peeling of the reinforcement sheet or the inner liner layer around an end portion of the reinforcement sheet or the inner liner layer in the tire circumferential direction after the pneumatic tire starts running, thereby being excellent in durability. The pneumatic tire of the present invention is a pneumatic tire including a sheet made of a thermoplastic resin or a thermoplastic resin composition obtained by blending an elastomer in a thermoplastic resin, the sheet being disposed inside the tire or in a surface portion of the tire, characterized in that a sheet in which a sheet end portion thereof extending in a tire circumferential direction is subjected to a tip-sharpening process is used as the sheet made of a thermoplastic resin or a thermoplastic resin composition obtained by blending an elastomer in a thermoplastic resin.