Ultra-Tensile Steel Bead Core for Tire Weight Reduction
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Solution Overview
Problem
Existing pneumatic vehicle tires face challenges in achieving high durability and weight reduction in the bead areas, where a large number of steel wires contribute significantly to the tire's weight, leading to increased rolling resistance and fuel consumption.
Innovation Solution
The use of ultra-tensile steel wires with a specific composition (C: 0.90 to 0.94%, Si: 0.40 to 0.58%, Mn: 0.25 to 0.40%, P: ≤ 0.02%, S: ≤ 0.02%, Cr: 0.15 to 0.25%, Cu: ≤ 0.04%, Al: ≤ 0.07%) for bead cores, allowing for a reduction in the number of steel wires by 7% to 15% while maintaining high strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large number of steel wires are used in the bead core, then the strength and durability of the tire bead area is improved, but the weight of the tire increases
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the steel wire, specifically increasing carbon content to 0.90-0.94 wt.% and silicon content to 0.40-0.58 wt.%, and adjusting other alloying elements. These compositional parameter changes enable the steel wire to achieve ultra-high tensile strength properties, allowing fewer wires to provide the same reinforcement effect, thus reducing tire weight while maintaining bead core strength.
2Reliability
If a large number of steel wires are used in the bead core, then the resistance to operational loads is improved, but the rolling resistance and fuel consumption increase
Solution Approach 1:
The patent changes the material parameters of the steel wire by optimizing the chemical composition with high carbon (0.90-0.94 wt.%) and silicon (0.40-0.58 wt.%) content, along with controlled amounts of manganese, chromium, copper, and other elements. These parameter changes produce steel wires with exceptional tensile strength, enabling the bead core to resist operational loads more effectively with fewer wires, thereby reducing rolling resistance and energy loss.
3Weight of moving object
If the number of steel wires is reduced, then the weight of the tire is decreased, but the strength and durability of the bead core may be compromised
Solution Approach 1:
The patent resolves this contradiction through parameter changes in the steel wire composition, specifically using ultra-high carbon (0.90-0.94 wt.%) and silicon (0.40-0.58 wt.%) content combined with optimized manganese (0.25-0.40 wt.%), chromium (0.15-0.25 wt.%), and other alloying elements. These compositional parameters enable each wire to achieve maximum strength, allowing a reduced number of wires to maintain adequate bead core strength while achieving weight reduction.
Solution Approach 2:
The patent employs composite material principles by creating a specialized steel wire composition that combines multiple alloying elements in specific proportions. The composite nature of this ultra-tensile steel, with its carefully balanced mix of carbon, silicon, manganese, chromium, copper, and other elements, produces a material with exceptional strength properties that enables fewer wires to provide sufficient reinforcement.
Data Source
Figure 1~3
AI summary
The invention relates to a bead core (1) for reinforcing the bead regions of pneumatic vehicle tires, which consists of a number of steel wires (2) having a diameter of 0.80 to 2.20 mm. Said steel wires consist of ultra-tensile steel with the following composition: C: 0.90 to 0.94 % by weight, Si: 0.40 to 0.58 % by weight, Mn: 0.25 to 0.40 % by weight, P: ≤ 0.020 % by weight, S: ≤ 0.020 % by weight, Cr: 0.15 to 0.25 % by weight, Cu: ≤ 0.040 % by weight, Al: ≤ 0.070 % by weight, remainder: iron and inevitable impurities.