Flat Steel Tire Wire Geometry to Reduce Boundary Cracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing steel wires with flat cross sections used in tires suffer from cracks at the boundary between linear and curved parts, leading to reduced durability and adhesion with rubber.
Innovation Solution
A steel wire with a cross-sectional shape featuring a pair of linear parts and a pair of curved parts, where the curved part includes first and second regions with specific radii of curvature and an angle between the linear and curved parts greater than or equal to 165 degrees, reducing the change in inclination at the boundary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If steel wire has a flat cross section with linear and curved parts, then weight is reduced and adhesion to rubber is improved, but cracks occur at the boundary between linear and curved parts reducing durability
Solution Approach 1:
The patent applies local quality by differentiating the curvature radius in different regions of the cross-section. The first region (near linear parts) has a smaller curvature radius (0.05-0.15mm) while the second region (center) has a larger curvature radius (0.13-0.20mm). This localized variation in geometric properties optimizes both adhesion to rubber and resistance to crack formation at specific locations.
Solution Approach 2:
The patent changes the geometric parameters of the cross-section, specifically the curvature radius and the angle between linear and curved parts. By controlling the angle to be 165 degrees or more and setting specific curvature radius ranges, the patent modifies the physical parameters to prevent crack formation while maintaining the flat shape for weight reduction and adhesion improvement.
2Reliability
If the curvature radius at the boundary is reduced to prevent cracks, then durability is improved, but the angle between linear and curved parts decreases affecting handling
Solution Approach 1:
The patent resolves this contradiction by applying different curvature radii to different regions. The first region near the linear parts has a smaller curvature radius (0.05-0.15mm) to prevent cracks, while the second region at the center has a larger curvature radius (0.13-0.20mm) to maintain the overall angle of 165 degrees or more, thus preserving handling and stability.
3Weight of moving object
If the cross section is made flatter to reduce weight, then weight reduction is achieved, but stress concentration increases leading to crack formation
Solution Approach 1:
The patent applies curvature to the cross-section by introducing rounded corners with specific curvature radii instead of sharp transitions. The first region has curvature radius 0.05-0.15mm and the second region has 0.13-0.20mm, which distributes stress more evenly across the flat cross-section, preventing stress concentration and crack formation while maintaining weight reduction benefits.
Data Source
AI summary
A steel wire having a cross section perpendicular to a longitudinal direction having a flat shape, and an outer shape of the cross section including a pair of linear parts opposing each other, and a pair of curved parts opposing each other and connecting the linear parts. The curved part includes a pair of first regions located at positions near the linear parts, and a second region located at a position between the pair of first regions, a radius of curvature, R1 of the first region is greater than or equal to 0.05 mm but less than 0.15 mm, and a radius of curvature, R2 of the second region is greater than or equal to 0.13 mm but less than or equal to 0.2 mm, and an angle between the linear part and the curved part is greater than or equal to 165 degrees.