Runflat Tire Sidewall Reinforcement via Fabric Barrier
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Solution Overview
Problem
Conventional run-flat tires face durability issues when operating at zero inflation pressure, often resulting in horizontal cracks due to increased stress, and current solutions to enhance durability either increase weight, size, or complexity, leading to higher production costs and time.
Innovation Solution
A run-flat tire design featuring crescent-shaped sidewall-reinforcing inserts with a fabric barrier made of parallel polymer cords, which redirects horizontal tears, thereby prolonging the tire's life without significant weight or production process changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the sidewall-reinforcing insert is increased to improve durability in zero psi state, then the run-flat durability is improved, but the tire weight and size increase
Solution Approach 1:
The patent uses a composite structure combining fabric barrier material with rubber inserts. The fabric barrier (made of polyester, nylon, or other synthetic fibers) is embedded within the rubber sidewall-reinforcing inserts, creating a composite material that provides both structural integrity and tear resistance. This composite approach allows the tire to maintain run-flat durability without needing to increase the overall thickness or weight of the rubber inserts alone.
Solution Approach 2:
The sidewall-reinforcing insert is divided into multiple components: an outer rubber portion and an inner fabric barrier portion. This segmentation allows each component to perform its specific function - the rubber provides structural support while the fabric barrier prevents tear propagation - without requiring the entire insert to be thicker, thereby avoiding increased weight.
2Reliability
If more rubber is added to reinforce the sidewalls to improve durability, then the run-flat durability is improved, but heat build-up increases leading to tire failure
Solution Approach 1:
By incorporating fabric barrier material into the sidewall-reinforcing insert, the patent creates a composite structure where the fabric layers reduce heat generation. The fabric barrier has lower hysteresis than solid rubber, meaning it generates less heat during flexing and deformation. This allows the tire to maintain structural integrity during run-flat operation without excessive heat build-up that would lead to failure.
3Reliability
If additional components are added to reinforce sidewalls to improve durability, then the run-flat durability is improved, but the tire design complexity and production time increase
Solution Approach 1:
The patent merges the fabric barrier and rubber insert into a single integrated sidewall-reinforcing component. Rather than adding separate reinforcement elements that would require multiple assembly steps, the fabric barrier is embedded within the rubber insert during manufacturing, creating a unified component that simplifies the overall tire structure and assembly process.
Solution Approach 2:
The fabric barrier within the sidewall-reinforcing insert serves multiple functions simultaneously: it prevents tear propagation, provides structural reinforcement, and reduces heat build-up. This multi-functionality means that a single component design achieves multiple durability goals without requiring additional separate components, thereby avoiding increased design complexity.
4Reliability
If additional components are integrated into other tire regions to reinforce sidewalls, then the run-flat durability is improved, but the overall tire performance and production efficiency are affected
Solution Approach 1:
The fabric barrier and rubber insert are combined into a single sidewall-reinforcing component that can be manufactured and assembled as one unit. This merging eliminates the need for separate assembly steps for multiple reinforcement components, thereby maintaining production efficiency while achieving improved run-flat durability.
Data Source
AI summary
A run-flat tire having a tread, an inner liner disposed beneath the tread, a body ply, and a pair of sidewalls axially spaced apart from one another is disclosed. The run-flat tire further includes a pair of sidewall-reinforcing portions each disposed in respective sidewall regions and each having a fabric barrier; a first sidewall-reinforcing insert between the fabric barrier and the inner liner; and a second sidewall-reinforcing insert disposed between the fabric barrier and the body ply. The fabric barrier extends not more than an entire length of the sidewall-reinforcing portion.