A type of all-steel radial truck tire with high bead durability

Abstract

This invention provides an all-steel radial truck tire with high bead durability. The bead, arranged radially from the inside to the outside, comprises: a bead wrap, a carcass cord, a rubber sheet, a hard triangular rubber, and a soft triangular rubber. The vertical height of the bead wrap is HWC.I, the vertical height of the rubber sheet is HJP, the vertical height of the hard triangular rubber is HHBF, the height of the lower sidewall of the tire's outer contour is LSH, the tire's section width is SW, and the section height is SH, satisfying the following relationships: 0.981≤SH / SW≤0.994, 0.520≤LSH / SH≤0.558, 0.581≤HWC.I / LSH≤0.605, 0.575≤HHBH / LSH≤0.638. This invention achieves an all-steel radial truck tire with high bead durability by establishing a correspondence between the outer contour design of the tire bead portion and the internal structure of the bead, and by optimizing the bead material.

Description

Technical Field

[0001] This invention relates to the field of tire technology, and specifically to an all-steel radial truck tire with high bead durability. Background Technology

[0002] In the heavy-duty market, due to the high-load operating environment, tire bead failure is one of the most common problems, such as bead cracks and internal bead cracks, which affect tire lifespan. To address these issues, tire design typically employs two main approaches:

[0003] I. The strength of the tire bead can be improved by directly adding reinforcing materials, such as adding a bead wrapping reinforcement layer or a nylon wrapping reinforcement layer, thereby enhancing the bead's load-bearing capacity. Chinese invention patent CN103754071A discloses an all-steel radial tire with internally reinforced bead and its manufacturing method. Specifically, it includes steel cord reverse wrapping layers and steel cord reinforcement layers on both sides of the carcass ply, with the steel cord reverse wrapping layers adhered between the carcass ply and the inner liner; the steel cord reinforcement layer is located between the carcass ply and the triangular rubber layer on the inner side of the bead. That is, by adding a bead wrapping layer between the carcass and the triangular rubber layer, the overall strength of the bead is improved, thereby enhancing the tire's high-load durability. Since the ratio of steel wire to rubber modulus in the bead area is typically 30K to 70K, and the bead area contains a lot of material and is subject to complex stress, stress concentration can easily occur when the tire changes its rolling direction, leading to material failure. Simply strengthening materials and components cannot effectively solve the problems of poor bead stability and low high-load resistance of all-steel radial tires.

[0004] II. Optimizing the wrapping height of the carcass material reduces stress and strain in the bead area, thereby extending the tire's service life. Chinese invention patent CN107685602A discloses an all-steel radial tire with high bead durability. In this tire, the carcass cord wraps around the steel wire bead, with a wrapping height hc = hf * a, where hf is the rim height and a coefficient a is 0.5–1.6. The lower end of the steel wire wrapping starts outside the horizontal tangent point of the carcass below the steel wire bead and covers the rim area. The upper end height of the steel wire wrapping is i = (Ra - hf - RimDia / 2) * b, where height i starts above the rim, Ra is the center radius of the tire crown, RimDia is the rim diameter, and a coefficient b is 40%–55%. In other words, by optimizing the relationship between the wrapping height of the carcass cord and the bead wrapping height and the rim height, stress and strain in the bead area can be reduced, effectively strengthening the tire's load-bearing capacity and thus improving bead durability. However, this method of improving tire bead durability by adjusting the height of the outer wrapping of the tire carcass and bead fabric has very limited practical application space, mainly due to two bottlenecks: First, from a design perspective, the adjustable height of the outer wrapping of the tire carcass and bead fabric is very limited. If it is set too low, for example, in this invention, the tire carcass wrapping height hc = hf * a, where hf is the rim height and the coefficient a is 0.5 to 1.6, if the coefficient is too low, such as 0.5, the tire carcass wrapping height is too low, and the tire carcass is at risk of being pulled out under ultra-high load conditions, such as a blowout. If the coefficient a is too high, the outer wrapping is set too high, meaning the wrapping end is too close to the maximum deformation area of ​​the tire. During tire operation, due to repeated bending and deformation, the outer wrapping end of the tire carcass or bead fabric is easily damaged. Based on experience, the actual operable space within the range of 0.5 to 1.6 is expected to be 1.0 to 1.5. In short, the application scope of this optimized external wrapping height design is definitely limited, and it is basically ineffective in high-load operating environments. Secondly, from a manufacturing perspective, this optimized setting of the external wrapping height of the tire carcass and bead requires a high degree of stability in the manufacturing process. Tires are rubber and plastic materials, and the process fluctuations are large, making it easy to deviate from the design accuracy requirements.

[0005] Therefore, it is crucial to design an easily implementable all-steel radial truck tire with high bead durability. Summary of the Invention

[0006] The technical problem to be solved by this invention is how to achieve an all-steel radial truck tire with high bead durability.

[0007] To address the aforementioned technical problems, this invention provides an all-steel radial truck tire with high bead durability. The bead, arranged radially from the inside out, comprises: a bead wrap, a carcass ply, a rubber sheet, a hard triangular rubber, and a soft triangular rubber. The vertical height of the bead wrap is HWC.I, the vertical height of the rubber sheet is HJP, the vertical height of the hard triangular rubber is HHBF, the height of the lower sidewall of the tire's outer contour is LSH, the tire's section width is SW, and the section height is SH, satisfying the following relationship:

[0008] 0.981≤SH / SW≤0.994

[0009] 0.520≤LSH / SH≤0.558

[0010] 0.581≤HWC.I / LSH≤0.605

[0011] 0.575≤HHBH / LSH≤0.638.

[0012] Furthermore, the film is configured as a single layer, and the film material must satisfy the following relationship:

[0013] 3.0≤M100≤3.4, where M100 is the strength of the film in MPa;

[0014] 5.6≤E'≤7.0, where E' is the modulus of the film in MPa.

[0015] Furthermore, the upper end point of the film is 10-30mm higher than the end point of the hard triangular adhesive; the lower end point of the film is set in the range of n-m, where n is the lowest point of the hard triangular adhesive and m is the midpoint of the height value of the hard triangular adhesive.

[0016] Furthermore, both the hard triangular adhesive and the soft triangular adhesive adopt a low heat generation formula, and the hard triangular adhesive satisfies 0.064≤tanδ≤0.188; the soft triangular adhesive satisfies 0.02≤tanδ≤0.078, where tanδ represents the heat generation of the adhesive.

[0017] Furthermore, the ratio of the hardness of the hard triangular adhesive to the hardness of the soft triangular adhesive is in the range of 1.16 to 1.36.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention achieves a high-bead-durability all-steel radial truck tire by establishing a correspondence between the outer contour design of the tire bead portion and the internal structure of the bead, as well as by optimizing the bead material. Attached Figure Description

[0020] Figure 1 This is a partial cross-sectional view of the tire of the present invention along the meridian direction;

[0021] Figure 2 This is a schematic diagram of an embodiment in which the SH / SW value is 0.987.

[0022] Figure 3 This is a schematic diagram of Comparative Examples 1, 2, 3, and 4, corresponding to SH / SW values ​​of 1.013, 1.000, 0.975, and 0.963 in this invention.

[0023] Figure 4 This is a schematic diagram of an embodiment in which the LSH / SH value is 0.539.

[0024] Figure 5 This is a schematic diagram of Comparative Example 5, in which the LSH / SH value is 0.503 in this invention;

[0025] Figure 6 This is a schematic diagram of an embodiment in which the HWC.I / LSH value is 0.605.

[0026] Figure 7 This is a schematic diagram of Comparative Example 6, in which the HWC.I / LSH value is 0.551 in this invention;

[0027] Figure 8 This is a schematic diagram of an embodiment in which the HHBF / LSH value is 0.638.

[0028] Figure 9 The diagrams for comparative examples 7 and 8 are shown for HHBF / LSH values ​​of 0.575 and 0.513, respectively, in this invention.

[0029] In the picture: 1. Bead wrapping; 2. Carcass cord fabric; 3. Rubber sheet; 4. Hard triangle rubber; 5. Soft triangle rubber. Detailed Implementation

[0030] To make the technical solutions and effects of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0031] Example

[0032] like Figure 1As shown, this invention provides an all-steel radial truck tire structure. The outer contour design includes a section height SH, a section width SW, and a lower sideplate height LSH. The internal structure includes a bead wrap 1, a carcass cord 2, a rubber sheet 3, a hard triangular rubber 4, and a soft triangular rubber 5 disposed between the carcass and the soft and hard triangular rubbers. The vertical height of the bead wrap 1 is HWC.I, the vertical height of the rubber sheet 3 is HJP, and the vertical height of the hard triangular rubber 4 is HHBF. The section width SW and section height SH of the tire have a ratio of 0.981≤SH / SW≤0.994, preferably SH / SW is 0.987. When SW is set too small, causing SH / SW to exceed the above range, the change in section width of the tire under inflation will increase too much, that is, the deformation near the horizontal axis position will be too large. When SW is set too large, causing SH / SW to be less than the above range, the change in section width of the tire under inflation will show a contraction trend, and the deformation will be negative, which will also lead to excessive deformation near the horizontal axis position. Both of these situations will cause excessive deformation of the bead area due to excessive deformation in the area near the horizontal axis, which is detrimental to the durability of the bead.

[0033] The tire structure has a relationship of 0.520≤LSH / SH≤0.558 between the lower sidewall height (LSH) and the tire section height (SH), with LSH / SH preferably being 0.539. When LSH / SH is set too small, i.e., the tire horizontal axis height (LSH) is set too small, the tire deformation area shifts downward, the stress deformation of each cord end point in the bead area is large, and the risk of cord end point cracking increases. When LSH / SH is set too large, i.e., the tire horizontal axis height (LSH) is set too large, the tire deformation area shifts upward. Although this is beneficial to the stress deformation of the bead area, it affects the stress deformation of the tire crown.

[0034] The tire structure has a relationship of 0.581 ≤ HWC.I / LSH ≤ 0.605 between the inner end height of the bead wrap and the lower side plate height of the outer contour. Preferably, HWC.I / LSH is 0.605. If HWC.I / LSH is set too high, the inner end height of the bead wrap will be too close to the horizontal axis, which is the area of ​​greatest tire deformation, thus increasing the risk of cracking at the inner end of the bead wrap. If HWC.I / LSH is set too low, the rigidity of the bead area will be directly reduced, and the bead durability will be significantly decreased. Therefore, the inner end height of the bead wrap has a reasonable range within which the tire's bead durability can be guaranteed.

[0035] The height HHBF of the upper end of the hard triangular rubber in this tire structure should satisfy the relationship 0.575≤HHBH / LSH≤0.638, preferably HHBH / LSH is 0.638. When the height of the upper end of the hard triangular rubber exceeds the above range, its end point is closer to the deformation area of ​​the horizontal axis, which can easily cause the hard triangular rubber to delaminate from the tire carcass during tire operation. When the height of the upper end of the hard triangular rubber is lower than the above range, the height of the hard triangular rubber end point is set too low, which will reduce the overall rigidity of the bead area and reduce the durability of the bead.

[0036] The tire structure features a rubber sheet placed between the tire carcass and the hard triangular rubber. This sheet is primarily designed to prevent premature tire damage caused by a gap between the carcass and the hard triangular rubber. The sheet material must consider comprehensive performance in terms of adhesion, fatigue, strength, and modulus. It should exhibit superior adhesion and tensile fatigue performance. The strength M100 (MPa) should satisfy 3.0 ≤ M100 ≤ 3.4, preferably M100 (MPa) = 3.2. The modulus E' (MPa) should satisfy 5.6 ≤ E' ≤ 7.0, preferably E' (MPa) = 6.3. The upper end of this sheet should be 10–30 mm higher than the end of the hard triangular rubber. When the height exceeds the above range, the endpoint is set too high and too close to the soft triangle rubber endpoint, which can easily cause the endpoints to overlap and cause air pockets. When the height is below the above range, the endpoint is set too low and too close to the hard triangle rubber endpoint, which can also easily cause air pockets. The height of the lower endpoint of the rubber sheet is set within the range of n to m (n is the lowest point of the hard triangle rubber, and m is the midpoint of the height value of the hard triangle rubber). When the height exceeds the above range, that is, the lower endpoint of the rubber sheet is set too high, the width of the rubber sheet is too small and cannot fully cover the interface between the tire carcass and the hard triangle rubber. When the height is below the above range, that is, the width of the rubber sheet is too long, which causes the material below the wire ring to accumulate too thickly.

[0037] Both the hard and soft triangular rubber compounds in this tire structure use a low-heat-generating formula. The tanδ of the hard triangular rubber needs to satisfy 0.064≤tanδ≤0.188, preferably tanδ=0.126; the tanδ of the soft triangular rubber needs to satisfy 0.02≤tanδ≤0.078, preferably tanδ=0.049. (Here, tanδ represents the heat generation of the rubber compound, which is the ratio of the rubber compound's viscous modulus to its elastic modulus). Considering the hardness ratio between the two components must satisfy the relationship of 1.16 ≤ Hd_hard / Hd_soft ≤ 1.36, an optimal Hd_hard / Hd_soft ratio of 1.26 is preferred. Using a low-heat-generating formula for both the soft and hard triangular rubbers is beneficial to the durability of the bead. Bead delamination or cracking due to heat generation is common, and a low-heat-generating formula effectively reduces heat generation in the bead material during tire operation, delaying the time it takes for the triangular rubber to detach and thus extending tire life. Furthermore, the hardness matching between the soft and hard triangular rubbers needs to be within a reasonable range. When Hd_hard / Hd_soft exceeds this range (i.e., the hardness ratio of the hard and soft triangular rubbers is too large), the material rigidity distribution in the bead area will be uneven, which is detrimental to bead durability. When Hd_hard / Hd_soft is less than this range (i.e., the hard triangular rubber is too soft), the material rigidity in the bead area is insufficient, which also affects the tire's bead durability.

[0038] To demonstrate the technical effectiveness of the technical solution adopted in this invention, this embodiment and the comparative example were verified and compared.

[0039] like Figure 2-3 As shown in Comparative Examples 1 to 4: When the SH / SW values ​​are 1.013, 1.000, 0.975, and 0.963 respectively, the change in tire section width from the initial state to the loaded state is as follows: the larger the change, the larger the absolute value of tire deformation, which is more detrimental to tire bead durability.

[0040]

[0041] like Figure 4-5 As shown in Comparative Example 5: When LSH / SH is 0.503, the shear strain at the end of the tire carcass at the bead area is as follows: the larger the shear strain, the greater the stress deformation at the bead area.

[0042]

[0043] like Figure 6-7 As shown in Comparative Example 6: When HWC.I / LSH is 0.551, the results of the machine tool internal crack test are shown. The higher the value, the better the tire bead durability.

[0044]

[0045] like Figure 8-9As shown in Comparative Examples 7-8: When HHBF / LSH values ​​are 0.575 and 0.513, the shear strain between the inner end of the bead wrapping and the tire body is as follows: the larger the value, the greater the stress deformation and the greater the risk of cracking inside the bead.

[0046]

[0047]

[0048] Comparative Example 9: When Hd hard / Hd soft is 1.56, the results of the machine tool internal crack test show that the higher the value, the better the tire bead durability.

[0049]

[0050] Comparative Example 10: When the soft triangular rubber tanδ = 0.104 and the hard triangular rubber tanδ = 0.314, the machine tool internal crack test results show that the higher the data, the better the tire bead durability.

[0051]

[0052] This invention optimizes the outer contour design of the bead region, such as the cross-sectional width SW, cross-sectional height SH, and lower sideplate height LSH, while ensuring other tire performance characteristics. Under the constraints of the technical parameters provided by this invention, the stress deformation of the tire bead region is minimized. Simultaneously, in terms of structural design, it establishes a correspondence between the internal structures, such as the height of the inner end point of the bead wrapping and the height of the hard triangular rubber, and the external contour parameters. Furthermore, it conducts in-depth exploration and verification of the heat generation and hardness matching of the soft and hard triangular rubbers in the formulation materials. This results in reduced stress deformation and heat generation in the entire bead region, especially in the area near the inner end point of the bead wrapping, thereby improving tire bead durability and extending tire lifespan.

[0053] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A type of all-steel radial truck tire with high bead durability, characterized in that, The tire bead, arranged radially from the inside to the outside, includes: a bead wrap (1), a carcass cord (2), a hard triangular rubber (4), and a soft triangular rubber (5). Both the bead wrap (1) and the carcass cord (2) include a main body and a reverse-wrapped portion. A rubber sheet (3) is positioned between the main body of the carcass cord (2) and the soft / hard triangular rubber without being reverse-wrapped. The axial inner end point of the bead wrap (1) has a vertical height of HWC.I, the upper end point of the rubber sheet (3) has a vertical height of HJP, the upper end point of the hard triangular rubber (4) has a vertical height of HHBF, the lower side plate height of the tire's outer contour is LSH, the tire's section width is SW, and its section height is SH, satisfying the following relationship: 0.981≤SH / SW≤0.994 0.520≤LSH / SH≤0.558 0.581≤HWC.I / LSH≤0.605 0.575≤HHBF / LSH≤0.

638.

2. The all-steel radial truck tire with high bead durability according to claim 1, characterized in that, The film (3) is set as a single layer, and the film (3) must satisfy the following relationship: 3.0≤M100≤3.4, where M100 is the strength of the film in MPa; 5.6≤E'≤7.0, where E' is the modulus of the film in MPa.

3. The all-steel radial truck tire with high bead durability according to claim 2, characterized in that, The upper end of the film (3) is 10-30 mm higher than the end of the hard triangular rubber; the lower end of the film (3) is set in the range of n-m, where n is the lowest point of the hard triangular rubber and m is the midpoint of the height value of the hard triangular rubber.

4. The all-steel radial truck tire with high bead durability according to claim 1, characterized in that, Both the hard triangular adhesive and the soft triangular adhesive use a low heat generation formula, and the hard triangular adhesive satisfies 0.064≤tanδ≤0.188; the soft triangular adhesive satisfies 0.02≤tanδ≤0.078, where tanδ represents the heat generation of the adhesive.

5. The all-steel radial truck tire with high bead durability according to claim 4, characterized in that, The ratio of the hardness of the hard triangular rubber to the hardness of the soft triangular rubber is in the range of 1.16 to 1.36.

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