Truck Tire Bead Structure to Prevent Bead Toe Lifting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Heavy-duty pneumatic tires used on trucks and buses often experience bead toe portion lifting after the first lifecycle, making retreading difficult and reducing marketability, as the bead core separates from the rim, leading to inflation issues.
Innovation Solution
The pneumatic tire design includes a pair of bead cores with a carcass layer folded back on each core, a steel cord reinforcing layer, and a rim cushion rubber, with specific distance and hardness configurations to prevent bead toe lifting by reducing outward pressure on the bead core during vulcanization, ensuring proper positioning and heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bead core is positioned closer to the bead toe portion to prevent lifting, then the risk of bead toe lifting is reduced, but the restriction on the carcass layer increases causing excessive outward pressure during vulcanization
Solution Approach 1:
The patent applies parameter changes by precisely controlling the distance A (2.0-4.0 mm) between the bead core outer projection point and the rim cushion rubber intersection point, and the distance B (0.6-1.4 mm) between the bead core inner projection point and the carcass cord. These parameter optimizations allow the bead core to be positioned close to the bead toe for lifting prevention while maintaining appropriate restriction on the carcass layer to control outward pressure during vulcanization.
2Reliability
If the distance A is increased to prevent bead toe lifting, then lifting resistance improves, but heat build-up in the bead portion increases
Solution Approach 1:
The patent resolves this contradiction through parameter optimization by setting distance A within the specific range of 2.0-4.0 mm. This optimized parameter allows sufficient spacing to prevent bead toe lifting while limiting the rubber volume between the bead core and steel cord reinforcing layer, thereby controlling heat build-up in the bead portion to within acceptable limits.
3Force
If the shortest distance B is increased to reduce carcass layer restriction, then outward pressure during vulcanization decreases, but the bead core moves away from the bead toe portion reducing lifting prevention effectiveness
Solution Approach 1:
The patent applies parameter changes by optimizing the shortest distance B between the bead core inner projection point and the carcass cord to be within 0.6-1.4 mm. This precise parameter control reduces carcass layer restriction and outward pressure during vulcanization while maintaining the bead core position close enough to the bead toe portion to prevent lifting.
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 prevents bead toe lifting, alleviates excessive restriction on the carcass layer, and suppresses heat build-up, enhancing the tire's durability and retreadability.
Implementation Method 1
an excessive increase in the rubber volume between the bead core and the steel cord reinforcing layer is suppressed. This allows the heat build-up of the bead portion to be suppressed to within an incident-free predetermined range
Data Source
AI summary
With a pneumatic tire not mounted on a rim, in a meridian cross-section a first line is parallel with an innermost bottom side of a bead core in a radial direction and passes through an outermost projection of the bead core in a lateral direction, a second line is orthogonal with the first line at the outermost projection, a third line is orthogonal with the first line and passes through an intersection of a rim cushion rubber, a distance between the second and third lines is 2.0 to 4.0 mm, a shortest distance between an innermost projection of the bead core in the lateral direction and a cord of a carcass layer is 0.6 to 1.4 mm, and a shortest distance between an innermost end of the bottom side of the bead core in the lateral direction and the cord of the carcass layer is 1.2 to 2.2 mm.