Pneumatic Tire Bead Stiffener Buffer Layer Design
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Solution Overview
Problem
Conventional pneumatic tires experience bending deformation and durability issues in the sidewall portion due to excessive stress from the rim flange, leading to peeling of the rubber material from the carcass cord and stiffener, which compromises the rigidity and durability of the tire.
Innovation Solution
A pneumatic tire design featuring a carcass body with a gradual decrease in distance between the carcass body and the carcass folded-back portion, using a first and second filling material with specific elongation moduli and placement to minimize distortion and prevent peeling, while maintaining the functionality of the stiffener in preventing sidewall falling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stiffener is provided between the carcass body and the carcass folded-back portion to enhance bead portion rigidity, then the rigidity of the bead portion is improved, but the rubber material between the stiffener and carcass cord is subjected to excessive tensile strain and distortion, leading to peeling and reduced durability
Solution Approach 1:
The patent changes the physical parameters of the rubber material by introducing a buffer layer with specific elastomeric properties. This buffer layer has different elasticity and tensile strength characteristics compared to the conventional rubber material, thereby reducing the tensile strain and distortion transmitted to the rubber material between the stiffener and carcass cord. The buffer layer absorbs and distributes the stress, preventing peeling while maintaining bead portion rigidity.
Solution Approach 2:
The patent introduces a buffer layer as an intermediary element between the stiffener and the carcass body. This buffer layer acts as a mediator that reduces the direct transmission of tensile strain and distortion from the stiffener to the rubber material. By placing this intermediary layer, the patent successfully decouples the rigid support function from the flexible bonding function, thereby preventing peeling while maintaining structural integrity.
2Force
If the sidewall portion is allowed to fall outside in the tire width direction under heavy load, then the tire can accommodate the load, but bending deformation occurs in the sidewall portion at the bead contact point, deteriorating rolling and pitch stability
Solution Approach 1:
The patent applies preliminary action by pre-positioning the buffer layer in the region where tensile strain occurs during load bearing. This buffer layer is installed beforehand to prevent the harmful effect of excessive distortion before it occurs during operation. The buffer layer is strategically placed in the sidewall portion between the stiffener and carcass cord to preemptively reduce tensile strain and prevent peeling under heavy load conditions.
3Adaptability or versatility
If the rubber material is repeatedly subjected to distortion under heavy loads, then the tire can handle varying loads, but the stiffener and rubber material become easy to peel off, causing deterioration in durability
Solution Approach 1:
The patent applies beforehand cushioning by introducing a buffer layer that absorbs and cushions the repeated distortion stresses before they can cause damage to the rubber material and stiffener interface. This buffer layer is positioned to preemptively reduce the amplitude of tensile strain during each loading cycle, thereby preventing the cumulative damage that leads to peeling and improving durability under repeated heavy load conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively reduces distortion in the rubber material, prevents peeling, and enhances the durability and rigidity of the tire's bead to sidewall portion, ensuring high-level performance under heavy loads.
Implementation Method 1
a first filling material and a second filling material sequentially arranged from the bead core toward outside in the tire radial direction, are provided between the carcass body and the carcass folded-back portion... the first filling material and the second filling material contacts with the rubber material forming the carcass body
Data Source
AI summary
The disclosed pneumatic tire (1) comprises a stiffener (31) and a rubber pad (32) which, disposed between a toroidal carcass body (21) and a folded-back carcass portion (22) folded back at a bead core (11), are arranged so as to be oriented radially outwards of the tire from the bead core (11). Further, from the rim baseline (BL), the height KSH to the end (31A) of the stiffener (31), the height OWH to the maximum carcass width (20W), and the height FH to the end (101A) of the rim flange (101) fulfill 0.2≦[(KSH−FH)/(OWH−FH)]≦0.28.