Pneumatic Tire Bead Helical Wire Staggered Rows Rim Mounting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pneumatic tires face challenges in maintaining both rim-shifting prevention and mountability on a rim, as the fastening force gradient is high and varies significantly with rim diameter, leading to increased fitting pressure and labor requirements.
Innovation Solution
The pneumatic tire features a core with a helical structure of non-stretchable wires, where cross-sections are aligned in a staggered manner, and a heel surface with a specific curvature and angle, reducing the fastening force gradient and fitting pressure while maintaining sufficient fastening force across various rim diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the diameter of the core of the bead is reduced to increase fastening force, then rim-shifting preventing performance is improved, but fitting pressure increases and mountability deteriorates
Solution Approach 1:
The core uses non-stretchable wires arranged in a specific pattern with varying row configurations (first row with N1 cross-sections, second row with N2 cross-sections where N2 = N1 + 1). This local structural optimization concentrates fastening force at critical contact points while maintaining overall core diameter, resolving the contradiction between high fastening force and acceptable fitting pressure
Solution Approach 2:
The heel surface is designed with a specific curvature radius (9-11mm) to optimize the contact area and pressure distribution between the bead and rim. This curved surface design allows the bead to engage the rim more gradually during mounting, reducing peak fitting pressure while maintaining sufficient fastening force
2Force
If the bead diameter is greatly reduced to obtain sufficient fastening force for lower limit rim diameter, then rim-shifting preventing performance is improved, but fitting pressure further increases for upper limit rim diameter
Solution Approach 1:
The invention optimizes multiple parameters simultaneously: the wire arrangement pattern (staggered rows with N2 = N1 + 1), the heel surface curvature radius (9-11mm), and the bottom surface angle (15°-20°). These parameter changes create a bead structure that adapts to different rim diameters within the standard range, maintaining both fastening force and acceptable fitting pressure across various rim sizes
Solution Approach 2:
The core structure with its specific wire arrangement and the heel surface geometry allow the bead to dynamically adjust its contact characteristics with the rim. The staggered wire pattern and curved heel surface enable the bead to optimize its engagement geometry depending on the rim diameter, providing adaptability across different rim sizes
3Ease of manufacture
If conventional bead structure is used, then manufacturing is simple, but fastening force gradient is great and varies significantly with rim diameter
Solution Approach 1:
The core is segmented into multiple rows of wires with specific cross-section arrangements (first row with N1 cross-sections, second row with N2 cross-sections). This segmentation allows precise control over fastening force distribution while maintaining a manufacturing process that can be implemented using conventional tire manufacturing techniques
Solution Approach 2:
The wire arrangement uses an asymmetric pattern where the second row has one more cross-section than the first row (N2 = N1 + 1). This asymmetric configuration optimizes the fastening force gradient and reduces variation with rim diameter, while still being manufacturable using standard wire winding and shaping processes
Data Source
Figure 1
Figure 2
Figure 3(a)~4
AI summary
In a tire (2), on a cross-section, three or more rows in each of which cross-sections (30) of a wire are aligned almost in the axial direction, are layered in the radial direction. The cross-sections (30) of the wire in a first row disposed on an innermost side in the radial direction and the cross-sections (30) of the wire in a second row layered outward of the first row are staggered. On a cross-section obtained by the tire (2) being cut at a plane perpendicular to the circumferential direction, an outline of a heel surface (36) of a bead (8) portion has an arc C that projects toward an outside of the bead (8) portion. A radius R of curvature of the arc C is greater than or equal to 8 mm and not greater than 12 mm.