A tire structure for solving internal bead cracking

Abstract

This invention provides a tire structure for solving internal bead cracking, belonging to the field of tire technology. The tire structure for solving internal bead cracking includes a crown portion, a carcass ply, and an inner liner. It also includes a bead wrapping layer disposed radially outside the inner liner. The bead wrapping layer extends from the center of the crown portion to both sides, bypassing the bead portion and wrapping back to the sidewall. The height of the back-wrapping endpoint of the bead wrapping layer is 10-20 mm higher than the height of the back-wrapping endpoint of the carcass ply. This invention incorporates a bead wrapping layer in both the inner liner and the carcass ply. This bead wrapping layer is a continuous, integral layer, which eliminates natural stress concentration points at the inner endpoints, thereby reinforcing the bead's load-bearing capacity. Furthermore, by optimizing the bead wrapping layer cord material, specifically using high-strength, fatigue-resistant nylon as the new wrapping material, a balance between strength and cost is achieved, thus preventing early internal cracking and extending tire life.

Description

Technical Field

[0001] This invention relates to the field of tire technology, and more specifically to a tire structure for solving the problem of internal cracking in the tire bead. Background Technology

[0002] For current all-steel radial tires, the load-bearing capacity is generally improved by adding bead wrapping. However, in the field of heavy-duty tires, the height of the inner end point of the bead wrapping reinforcement layer is generally increased to improve the bead load-bearing capacity. But increasing the height of the inner end point of the bead wrapping reinforcement layer can easily place this point near the deformation zone. Since the inner end point is a stress concentration point, and the inner cavity side is only protected by the inner liner, stress shear tearing of the inner liner layer area A at the inner end point of the bead wrapping can cause internal bead cracking failure, leading to instantaneous tire failure. For details, please refer to... Figure 1 .

[0003] The mechanism of internal bead cracking failure has two aspects. First, the addition of a reinforcing layer to the bead wrapping creates a natural stress concentration point at the inner end of the wrapping, which is unavoidable. Without this reinforcement, the bead's load-bearing capacity is insufficient. Second, the inner end of the bead wrapping is generally located near the deformation zone, making it more susceptible to shear deformation under high load conditions, thus leading to internal cracking failure. Existing technology can reduce the inner end of the bead wrapping away from the deformation zone, but this reduces its effectiveness in improving bead load-bearing capacity and negates its reinforcing effect. Furthermore, because internal cracking failures generally occur early, are not externally observable, and occur without warning, they pose a high potential risk. Therefore, a tire structure needs to be designed to balance these issues. Summary of the Invention

[0004] This invention provides a tire structure that solves the problem of internal bead cracking, which can both ensure the performance of the reinforced bead and completely eliminate the probability of internal cracking failure, thereby improving tire durability and extending tire service life.

[0005] A tire structure for solving internal bead cracking includes a crown portion, a carcass ply, and an inner liner, and further includes a bead wrapping layer disposed radially outside the inner liner. The bead wrapping layer extends from the center of the crown portion to both sides, bypasses the bead portion, and wraps back to the sidewall portion. The height of the back-wrapping end of the bead wrapping layer is 10-20 mm higher than the height of the back-wrapping end of the carcass ply.

[0006] Preferably, the bead covering layer is made of nylon.

[0007] Preferably, the bead covering layer has a dry heat shrinkage rate of ≤2.0 under the condition of 150℃*30min.

[0008] Preferably, the tensile modulus of the bead covering layer is ≥3000 MPa.

[0009] Preferably, the bead covering layer has a strength retention rate of over 90% after 50,000 fatigue cycles.

[0010] Preferably, the bead wrapping layer meets the requirement that the material adhesion force reaches 130N / 5mm under vulcanization conditions of 145℃*30min.

[0011] As can be seen from the above technical solutions, the present invention has the following beneficial effects: In the present invention, a bead wrapping layer is provided in the inner liner layer and the carcass ply layer. The bead wrapping layer is an integrally connected layer, which can eliminate the natural stress concentration points at the inner end points, thereby enhancing the load-bearing performance of the bead. At the same time, by optimizing the cord material of the bead wrapping layer, that is, by using high-strength fatigue-resistant nylon as the new wrapping material, the strength and cost are balanced, thereby avoiding the occurrence of early internal cracking failure of the tire and improving the service life of the tire. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the areas in existing tires prone to internal cracking. Figure 2 This is a schematic diagram of the tire structure provided in this application; Figure 3 This is a schematic diagram of an existing tire structure.

[0013] In the diagram: 10, tire crown; 20, tire carcass ply; 30, inner liner; 40, bead wrapping; 50, bead; 60, sidewall. Detailed Implementation

[0014] A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0015] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions: (Refer to...) Figure 2A tire structure for solving internal bead cracking includes a crown portion 10, a carcass ply 20, an inner liner 30, a bead wrapping layer 40, a bead portion 50, and a sidewall portion 60. In this embodiment, the two ends of the carcass ply 20 bypass the bead portion 50 and wrap around to the sidewall portion 60. The bead wrapping layer 40 is disposed radially outside the inner liner 30, and the bead wrapping layer is an integrally connected structure. Specifically, the bead wrapping layer 40 is located between the inner liner 30 and the carcass ply 20. The bead wrapping layer extends from the center of the crown portion to both sides to bypass the bead portion 50, and the two ends of the bead wrapping layer wrap around to the sidewall portion 60. The height of the wrapping end of the bead wrapping layer 40 is greater than the height of the wrapping end of the carcass ply 20. The bead wrapping layer 40 is 10-20mm higher than the carcass ply 20. This design optimizes the traditional separate left and right bead wrapping layers into a fully connected bead wrapping layer, eliminating the natural stress concentration point at the inner end and thus reinforcing the bead's load-bearing capacity. Furthermore, the height of the bead wrapping layer's reverse end point is 10-20mm higher than that of the carcass ply 20. Since internal bead cracks are generally an early failure, if internal cracks do not recur, external cracks are likely to occur. Therefore, to protect the carcass reverse end point, the bead wrapping layer's reverse end point must be 10-20mm higher than the carcass ply's reverse end point to disperse stress concentration, balance the rigidity distribution of the deformation area, improve bead durability, and ultimately extend tire life.

[0016] As a preferred technical solution in this embodiment, the bead covering layer 40 is made of nylon. By using high-strength, fatigue-resistant nylon as the new covering material, the strength and cost can be balanced, thereby avoiding early internal cracking failure of the tire and improving the tire's service life.

[0017] In some embodiments, the nylon material of the bead covering layer 40 is manufactured using a special process to ensure that the material properties meet the following requirements: The material constituting the bead covering layer 40 has a dry heat shrinkage rate of ≤2.0 under the condition of 150℃*30min; Furthermore, the tensile modulus of the 40mm bead wrapping material is ≥3000 MPa; The bead wrapping layer 40 has excellent fatigue resistance, and its strength retention rate reaches more than 90% after 50,000 fatigue cycles. Meanwhile, considering the adhesion performance between the material and rubber, and to prevent the material from falling off during long-term use, the ASTM test method was adopted, that is, under the vulcanization conditions of 145℃*30min, the material adhesion force reaches 130N / 5mm.

[0018] Reference Figure 2 , Figure 3To verify the technical effectiveness of this application's solution in enhancing the load-bearing capacity of the tire bead, the tire structure provided in this application and the traditional tire structure with non-connected left and right bead wrapping were tested separately. Comparisons were made in terms of positioning, dimensional stability, adhesion performance, and bead stress and strain. The comparison results are shown in Table 1 below. The rigidity simulation analysis and bead stress and strain simulation analysis both used a 12.00 R20 tire as an example, with the analysis conditions being: air pressure 900 kPa and load 4000 kg.

[0019]

[0020] Table 1 - Performance Comparison of Tire Structures in This Application and Traditional Cases As can be seen from the table above, the tire structure corresponding to the present application is significantly superior to the existing solution in terms of molding positioning, dimensional stability, adhesion performance, rigidity, and bead stress and strain compared to the traditional tire structure. This is because the present application adopts an integrally connected bead wrapping layer, which can fundamentally eliminate the natural stress concentration points at the inner end, thereby enhancing the bead's load-bearing capacity.

[0021] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A tire structure for solving internal bead cracking, comprising a crown portion (10), a carcass ply (20), and an inner liner (30), characterized in that, It also includes a bead wrapping layer (40) disposed on the radially outer side of the inner liner layer. The bead wrapping layer extends from the center of the crown to both sides to bypass the bead portion (50) and wraps back to the side portion (60). The height of the back-wrapping end of the bead wrapping layer (40) is 10-20 mm higher than the height of the back-wrapping end of the carcass ply layer (20). The bead covering layer (40) is made of nylon.

2. The tire structure for solving internal bead cracking according to claim 1, characterized in that, The bead covering layer (40) satisfies the requirement that the dry heat shrinkage rate is ≤2.0 under the condition of 150℃*30min.

3. The tire structure for solving internal bead cracking according to claim 1, characterized in that, The tensile modulus of the bead wrapping layer (40) is ≥3000 MPa.

4. The tire structure for solving internal bead cracking according to claim 1, characterized in that, The bead wrapping layer (40) is required to maintain a strength retention rate of over 90% after 50,000 fatigue cycles.

5. The tire structure for solving internal bead cracking according to claim 1, characterized in that, The bead wrapping layer (40) meets the requirement that the material adhesion force reaches 130N / 5mm under vulcanization conditions of 145℃*30min.

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