Pneumatic Tire Bead Core Segmented Wire Rings
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Solution Overview
Problem
Conventional pneumatic tire bead cores either compromise ride comfort for improved steering/handling stability and uniformity due to the use of twisted or monofilament cords, as they either reduce flexibility or increase binding force, failing to achieve a balanced performance.
Innovation Solution
A pneumatic tire design featuring a bead core composed of spirally overlap-wound wire rings, including a twisted cord for flexibility and a monofilament cord for rigidity, with the twisted cord having a lower bending rigidity and higher elongation to balance ride comfort and steering/handling stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a twisted cord is used as bead wire, then flexibility of the bead portion is improved, but binding force between bead portion and wheel rim is reduced
Solution Approach 1:
The bead core is segmented into multiple wire rings arranged in the tire axial direction, with each ring made of twisted cord. This segmentation allows the bead core to provide flexibility through the twisted cord structure while maintaining adequate binding force through the distributed ring structure
Solution Approach 2:
The invention changes the parameters of the twisted cord by specifying a bending rigidity of 100 N to 260 N and elongation of not less than 0.03% under specific tension conditions. These parameter adjustments optimize the balance between flexibility and binding force
2Strength
If a monofilament cord is used as bead wire, then binding force between bead portion and wheel rim is increased, but flexibility of the bead portion is reduced
Solution Approach 1:
Different portions of the bead core are given different properties by using twisted cord in some wire rings to provide flexibility where needed, while the overall bead core structure maintains sufficient binding force through the arranged configuration of multiple rings
Solution Approach 2:
The bead core uses composite construction with multiple wire rings made of twisted cord, combining the flexibility benefits of twisted structure with the structural integrity of multiple arranged rings to achieve balanced performance
3Ease of operation
If bead core uses twisted cord, then ride comfort performance is improved, but steering/handling stability is deteriorated
Solution Approach 1:
By precisely controlling the bending rigidity (100 N to 260 N) and elongation (not less than 0.03%) parameters of the twisted cord, the invention optimizes the balance between ride comfort and steering/handling stability
Solution Approach 2:
The segmented wire ring structure distributes the mechanical properties throughout the bead core, providing sufficient flexibility for ride comfort while maintaining the structural stability needed for steering/handling performance
Data Source
AI summary
A pneumatic tire 1 comprises an annular bead core 5 embedded in each bead portion 4 of the tire. The bead core 5 is composed of a plurality of wire rings 10 each of which is made of a spirally overlap-wound bead wire 11 and which are arranged in the tire axial direction. The wire rings 11 include a first ring 13 whose bead wire 11 is a twisted cord 13a made of a plurality of filaments 15 twisted together, and a second ring 14 whose bead wire 11 is a monofilament cord 14a made of a single filament.