Pneumatic Tire Bead Asymmetry Rim Mounting Eccentricity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pneumatic tires often experience uneven wear due to eccentric engagement with the rim wheel, particularly in low wear conditions like long-distance transport, where correct positioning is not maintained.
Innovation Solution
A pneumatic tire design featuring a pair of bead portions with specific geometric and structural features, including a carcass supported by bead cores, a steel cord reinforcing layer, and a bead rubber layer, optimized for mounting on a 15° tapered rim, with precise dimensions and angles to prevent eccentric engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bead portion design is used, then manufacturing is simpler, but eccentric engagement occurs causing uneven wear
Solution Approach 1:
The bead base portion is designed with asymmetric geometry where the bead heel side has a different profile than the bead toe side. Specifically, the bead heel includes a rim contact surface with a specific angle (15-25 degrees) relative to the tire equatorial plane, while the bead toe side has a different configuration. This asymmetric design creates preferential engagement characteristics that guide the bead portion to engage correctly with the rim, suppressing eccentric engagement and preventing uneven wear.
Solution Approach 2:
Different regions of the bead portion are given different structural properties to optimize their specific functions. The bead heel region is designed with a specific angle and surface characteristics for optimal rim contact and engagement, while the bead toe region has different geometry for proper positioning. The bead core is positioned at a specific offset from the center of the bead base portion, creating local variations in mass distribution and engagement characteristics that prevent eccentric mounting.
2Manufacturing precision
If bead portion geometry is optimized to suppress eccentric engagement, then positioning accuracy improves, but manufacturing precision requirements increase
Solution Approach 1:
The invention specifies precise geometric parameters for the bead portion, including the bead heel angle (15-25 degrees), the offset distance between the bead core center and bead base portion center (5-15 mm), and the relative positions of the bead core, carcass, and belt layers. By optimizing these parameters within specific ranges, the design achieves effective suppression of eccentric engagement while providing clear manufacturing specifications that balance precision requirements with manufacturability.
3Duration of action of stationary object
If correct engagement positioning is not maintained, then tire durability decreases due to uneven wear, but in low wear conditions like long hauls, uneven wear becomes significant
Solution Approach 1:
The bead portion is designed with pre-configured geometric features during manufacturing that prevent eccentric engagement from occurring in the first place. The asymmetric bead base portion geometry, positioned bead core, and specific rim contact surface angles are built-in characteristics that guide correct engagement during mounting. This preliminary design prevents the development of uneven wear patterns before they can occur during service, extending tire life particularly in long-haul applications where wear accumulation is significant.
Data Source
AI summary
A pneumatic tire mountable on a 15° tapered specified rim, the pneumatic tire including a bead portion, bead core, a carcass, a steel cord reinforcing layer, and a bead rubber layer. A distance from a second line segment to a third line segment is from 4 mm to 8 mm, and a ratio R2/R1 is from 0.935 to 0.975, wherein R2 is a tire radius at a bead toe of a bead base portion and R1 is a tire radius at a bead heel.