Polyester Belt Cover Tire Structure for Steering Stability
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Solution Overview
Problem
Existing pneumatic tires face a trade-off between improved steering stability, durability, and rolling resistance, particularly when using high-angle belt structures with polyester fiber cords, which can lead to heat generation and durability issues.
Innovation Solution
A pneumatic tire design incorporating a high-angle belt structure with a polyester fiber cord for the belt cover layer, specifying a range of elongation under load, peak temperature, and peak loss modulus E' to suppress heat generation and enhance durability while maintaining steering stability and reducing rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a polyester fiber cord is used as the belt cover cord to improve steering stability, then the rigidity of the tread portion is increased and steering stability is improved, but the cord tends to generate heat and durability may be deteriorated
Solution Approach 1:
The patent applies parameter changes by precisely controlling the elongation under load of the polyester fiber cord within 2.0% to 4.0%, and setting the peak temperature of loss modulus E'' at 115°C or higher with a peak value of 12000 MPa or less. These specific parameter ranges optimize the balance between steering stability and heat generation, resolving the contradiction between improved steering stability and durability concerns.
2Temperature
If a high angle belt structure is adopted to reduce heat generation and weight, then weight reduction and ride comfort are achieved, but the cornering power may decrease and steering stability may degrade
Solution Approach 1:
The patent applies local quality by differentiating the functions of different layers: the belt layers use a high cord angle (27° to 40°) to reduce heat generation and weight, while the belt cover layer uses a polyester fiber cord with specific elongation properties (2.0% to 4.0%) to maintain steering stability. This localized optimization of different layers resolves the contradiction between heat reduction and steering stability.
3Weight of moving object
If the cord angle of the belt layer is increased to reduce heat generation, then heat generation and weight are reduced, but the cornering power decreases and steering stability degrades
Solution Approach 1:
The patent applies local quality by assigning different cord angles to different layers: the belt layers have a high cord angle (27° to 40°) for weight reduction and heat generation reduction, while the belt cover layer has cords oriented in the tire circumferential direction to maintain steering stability. This layered differentiation resolves the contradiction between weight reduction and steering stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves improved steering stability, durability, and reduced rolling resistance by optimizing the properties of the polyester fiber cord in the belt cover layer, balancing the advantages of high elasticity with heat management.
Implementation Method 1
The PET fiber cord has higher elasticity than the nylon 66 fiber cord. Therefore, when the PET fiber cord is used as the belt cover cord, the rigidity of the tread portion of the pneumatic tire is increased
Implementation Method 2
since the PET fiber cord tends to generate heat, there is a concern that durability may be deteriorated
Data Source
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AI summary
Provided is a pneumatic tire that can provide improved steering stability while satisfactorily maintaining durability and rolling resistance. A pneumatic tire includes a tread portion (1), a pair of sidewall portions (2), a pair of bead portions (3), a carcass layer (4) mounted between the pair of bead portions (3, 3), a plurality of belt layers (7) in which belt cords intersect each other between the belt layers disposed on an outer circumferential side of the carcass layer (4) in the tread portion (1), and a belt cover layer (8) including a belt cover cord (8C) oriented in the tire circumferential direction disposed on an outer circumferential side of the belt layers (7). The belt cover cord (8C) is a polyester fiber cord having an elongation under a load of 2.0 cN/dtex ranging from 2.0% to 4.0%. When measured at a frequency of 20 Hz, an initial load of 300 g, a strain of ±0.1%, and a temperature increase rate of 2°C/minute, a peak temperature of a loss modulus E" of the polyester fiber cord is 115°C or higher, and a peak value of the loss modulus E" is 12000 MPa or less. A cord angle θ of the belt layer (7) with respect to the tire circumferential direction ranges from 27° to 40°.