Hybrid Bead Core for Heavy Vehicle Tires
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Solution Overview
Problem
Heavy vehicle tires face challenges in maintaining performance and endurance under high pressures without increasing the weight of the bead core, as existing bead structures are not optimized for heavy loads and high inflation pressures.
Innovation Solution
The use of hybrid bead cores composed of multiple spirally-wound reinforcements made from different materials, such as metal and nonmetallic wires, where the innermost wire has a higher elongation at break than the outer wires, allowing for reduced metal usage and increased burst strength without increasing the overall weight or robustness of the bead core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional bead core structures are used in heavy vehicle tires, then the tire can maintain structural integrity under high pressure, but the bead core weight increases and burst strength is limited
Solution Approach 1:
The bead core is constructed as a composite structure combining metal wire (providing tensile strength and pressure resistance) and nonmetallic wire (providing flexibility and weight reduction). This composite approach allows the tire to withstand high inflation pressures and heavy loads while reducing overall bead core weight compared to traditional all-metal constructions.
Solution Approach 2:
Different regions of the bead core are constructed with different material compositions optimized for their specific functional requirements. The innermost reinforcement uses metal wire for maximum strength where pressure is highest, while outer reinforcements incorporate nonmetallic wire where flexibility and weight reduction are more critical, creating a gradient of material properties throughout the bead core structure.
2Reliability
If more metal wire is used to increase burst strength, then the tire can withstand higher pressures, but the overall weight of the tire increases
Solution Approach 1:
The invention optimizes the elongation at break parameter of the innermost wire relative to outer wires, creating a specific gradient in material ductility. This parameter optimization allows the bead core to deform elastically under high pressure without failure, improving pressure endurance while using less total metal content, thereby reducing weight.
3Force
If the bead core structure is made more robust to handle heavy loads, then load capacity increases, but the tire performance and speed are reduced due to increased weight
Solution Approach 1:
The hybrid metal-nonmetallic wire construction provides high load capacity through the metal component's strength while the nonmetallic component reduces overall density. This allows the bead core to support heavy vehicle loads without the excessive weight that would otherwise limit tire rotational speed and vehicle performance.
Data Source
Figure 1
Figure 2~3
AI summary
A vehicle tire having two beads comprising metal / non-metal hybrid bead cores intended to come into contact with a wheel rim and a carcass reinforcement anchored by a bead core located in each bead, wherein the bead core includes a plurality of separate spirally-wound reinforcements that are placed adjacent to one another in a substantially axial arrangement. The innermost of the spirally-wound reinforcements, the one farthest from the reinforcement turn-up, is formed of a first metal wire and there is a nonmetallic wire forming a second reinforcement. The metal wire has an elongation at break that is at least 40% greater than an elongation at break of the nonmetallic wire or alternatively at least 100% or at least 200% greater than the elongation at break of the nonmetallic wire. Optionally wires of other metals or nonmetals may be useful for forming others of the plurality of spirally-wound reinforcements.