Utility Tire Protection Layer Steel Filament Strength
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Solution Overview
Problem
Commercial vehicle tires with a three-layer belt package face durability issues due to stone penetration and corrosion, which reduces their load-carrying capacity, durability, and retreadability, especially when the protective layer fails to adequately intercept stones and other objects.
Innovation Solution
The tire features a protective layer with steel filaments of uniform diameter between 0.30 to 0.45 mm, assigned to strength class ST or higher, arranged in a specific construction such as 1 x 0.32 ST + 5 x 0.32 ST, providing enhanced stone penetration resistance and durability while maintaining a balance between durability and rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steel cords of lower strength class (HT) are used in the protective layer, then production costs are reduced, but the protective layer fails to adequately intercept stones and other objects, reducing durability
Solution Approach 1:
The patent changes the strength class parameter of steel filaments from HT (3800 MPa) to ST (3980 MPa) or UT (4400 MPa). This parameter change increases the protective layer's ability to intercept stones and objects, improving durability by 11% in energy absorption, while the uniform diameter specification (0.30-0.45 mm) maintains manufacturing consistency
Solution Approach 2:
The patent applies different quality standards to different regions of the belt package. The protective layer specifically uses ST or UT class steel filaments with uniform diameter, while working layers may use different configurations. This local quality enhancement focuses resources where stone interception is most critical
2Reliability
If steel filaments of varying diameters are used in the protective layer, then manufacturing flexibility is improved, but reinforcement fractures occur more frequently, reducing durability
Solution Approach 1:
The patent mandates that all steel filaments in the protective layer have the same diameter within the range of 0.30-0.45 mm. This homogeneity eliminates weak points caused by diameter variations, preventing reinforcement fractures and improving durability. The uniform construction simplifies the filament structure while enhancing reliability
Solution Approach 2:
The patent segments the protective layer into discrete steel filaments of uniform diameter, each contributing equally to stone interception. This segmentation with uniformity ensures that no single filament becomes a weak point, and the collective structure resists fractures more effectively
3Reliability
If the protective layer uses thicker steel cords to intercept stones, then stone penetration resistance is improved, but the tire weight increases
Solution Approach 1:
The patent changes the strength class parameter to ST or UT, which provides higher tensile strength per unit area. This allows the use of thinner filaments (0.30-0.45 mm diameter) that achieve the same or better stone interception performance, reducing tire weight while maintaining or improving durability
Solution Approach 2:
The patent uses composite construction of multiple steel filaments stranded together in the protective layer. This composite structure provides enhanced stone penetration resistance through collective strength, while the optimized filament count and diameter reduce overall material usage and weight compared to single thick cords
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a radial-type pneumatic vehicle tire, particularly a utility vehicle tire having a belt package (3) consisting of at least three layers (8, 9, 10), specifically two working layers (8, 9) and a protection layer (10), arranged radially on the outside in relation to the working layers (8, 9), wherein the protection layer (10) has reinforcing supports (11) consisting of one or more steel filaments (12), which are stranded together, wherein the steel of the steel filaments (12) of the reinforcing supports (11) of the protection layer (10) has a strength class ST or a higher strength class, the strength class ST having a tensile strength in MPa of 3980-2000 d and the strength class UT having a tensile strength in MPa of 4400-2000 d, and d being the diameter of a steel filament in mm.