All-steel radial tire bead

Abstract

This invention provides a bead for an all-steel radial tire, relating to the technical field of tire structure. It includes a triangular rubber compound comprising a lower triangular rubber compound and an upper triangular rubber compound. The lower triangular rubber compound has a low, triangular wedge-shaped cross-section, and the upper triangular rubber compound sits atop the lower triangular rubber compound. A curved surface forms a transition interface between the lower and upper triangular rubber compounds. This curved surface includes a first transition arc, a second transition arc, and a third transition arc, which are sequentially connected on the tire's radial cross-section to form a continuous transition interface. The ratio of the height H1 at the top of the lower triangular rubber compound to the total height H of the triangular rubber compound is 0.3 to 0.5. This invention solves the technical problem of stress concentration at the junction of the upper and lower rubber compounds, reducing tire durability and load-bearing capacity. It achieves improved transition performance from the bead to the sidewall, enhanced durability, and provides the tire with a longer service life and higher reliability under heavy load conditions.

Description

Technical Field

[0001] This invention relates to the field of tire structure technology, and in particular to an all-steel radial tire bead. Background Technology

[0002] In all-steel radial tires, the bead area is a crucial region connecting the bead wires to the sidewall. Because the bead wire is made of steel and is extremely rigid, while the sidewall ply is relatively soft and elastic, a direct connection between the two is highly susceptible to breakage due to the significant difference in stiffness. Therefore, a triangular rubber insert is used in this area to provide a buffer transition between the bead and sidewall, offering support to the sidewall while ensuring a smooth transition and maintaining the tire's basic performance.

[0003] In the prior art, for example, Chinese patent application number CN201721143567.X discloses a radial tire with a composite rubber core, mainly employing a double-layer design combining hard and soft triangular rubbers. A layer of high-hardness lower triangular rubber is bonded above the steel wire bead to resist flexural deformation of the bead area; a layer of low-hardness upper triangular rubber is then wrapped above the lower triangular rubber to withstand flexural fatigue caused by repeated pressure and stretching at the reverse-wrapped end of the tire carcass. In addition, there are improved solutions that reduce height and increase hardness, i.e., increasing sidewall deformation by reducing the height of the triangular rubber, while using high-hardness rubber materials with a Shore D78 or higher to maintain bead support strength and handling performance.

[0004] However, the existing structure still has the following technical problems: First, the interface between the upper and lower rubber materials is mostly a straight interface or a simple slope. The properties of the rubber materials change abruptly at the interface, which can easily cause stress concentration and lead to fatigue damage at the joint of the rubber layers. In addition, if the upper position of the lower triangular rubber (hard rubber core) is set too high, it will generate a large shear stress near the reverse end of the tire carcass ply, which can easily lead to early damage and cracking at the bead. Summary of the Invention

[0005] The purpose of this invention is to provide an all-steel radial tire bead to alleviate the technical problem in the prior art where stress concentration occurs at the junction of the upper and lower rubber materials, reducing tire durability and load-bearing capacity.

[0006] The all-steel radial tire bead provided by the present invention includes: a bead wire, a triangular rubber covering the outside of the bead wire, a carcass ply covering the outside of the triangular rubber, and the upper end of the triangular rubber extending outward along the radial direction of the tire and smoothly transitioning to the sidewall rubber. The triangular rubber consists of a lower triangular rubber and an upper triangular rubber. The lower triangular rubber has a low triangular wedge-shaped cross section, and the upper triangular rubber is located above the lower triangular rubber. The transition interface between the lower and upper triangular rubbers forms an arc surface. The curved surface includes a first transition arc, a second transition arc, and a third transition arc that are sequentially connected on the radial section of the tire to form a continuous transition interface; The ratio of the height H1 at the top of the lower triangular adhesive to the total height H of the triangular adhesive is 0.3 to 0.5.

[0007] Furthermore, taking the upper surface of the bead wire as the height reference plane, the starting point of the first transition arc is the highest point H1 of the lower triangular rubber, and the ending point of the first transition arc is P1; the starting point of the third transition arc is P2, and the ending point of the third transition arc is the intersection of the bottom end of the lower triangular rubber and the outline of the tire carcass ply. Wherein, the ratio of the longitudinal length h1 of P1 to the height H1 of the top of the lower triangular rubber is 0.3 to 0.4, and the lateral length d1 of P1 is the horizontal distance between P1 and the middle extension line of the bead wire; the ratio of the longitudinal length h2 of P2 to h1 is 0.2 to 0.3, and the lateral length d2 of P2 is the horizontal distance between P2 and the middle extension line of the bead wire.

[0008] Furthermore, the longitudinal length h1 of the end point P1 of the first transition arc is 13-20 mm, and d1 is 2-5 mm; the longitudinal length h2 of the starting point P2 of the third transition arc is 1 mm-5 mm, and d2 is 4-8 mm.

[0009] Furthermore, the radius of curvature of the first transition arc ranges from 30 to 120 mm, the radius of curvature of the second transition arc ranges from 5 to 30 mm, and the radius of curvature of the third transition arc ranges from 2 to 12 mm.

[0010] Furthermore, one end of the second transition arc is tangent to the first transition arc at P1, and the other end of the second transition arc is tangent to the third transition arc at P2, thus achieving tangential continuity of the three arc segments.

[0011] Furthermore, the height H1 of the top of the lower triangular adhesive is 20-60mm, and the total height H of the triangular adhesive is 60-120mm.

[0012] Furthermore, the height of the upper triangular adhesive is the difference between the total height H of the triangular adhesive and the height H1 of the top of the lower triangular adhesive.

[0013] Furthermore, the Shore A hardness of the lower triangular rubber is 80-90, and the Shore A hardness of the upper triangular rubber is 60-70.

[0014] Beneficial effects: The all-steel radial tire bead provided by this invention solves the stress concentration problem of traditional triangular rubber structures through a low-profile triangular wedge-shaped lower triangular rubber and a three-segment continuous transition arc surface. The lower triangular rubber adopts a low-profile triangular wedge structure with a height ratio H1 / H of 0.3 to 0.5. The high-hardness lower triangular rubber provides bead support, reducing tire deformation at the bead area and shear stress at the reverse-wrapping end of the tire carcass steel wires under high load conditions. Furthermore, it does not extend excessively upwards, thus avoiding the introduction of excessive rigidity in the upper and middle parts of the tire sidewall. The low-hardness upper triangular rubber provides a good elastic transition, mitigating stress concentration in the transition area from the bead to the tire sidewall and reducing heat generation during driving, thereby improving the fatigue resistance of the bead area.

[0015] The curved surface between the upper and lower triangular rubber sections is formed by the sequential connection of the first, second, and third transition arcs, creating a continuous segmented interface. This achieves a smooth transition of the rubber compound's properties from high to low modulus, significantly reducing stress abrupt changes at the interface and delaying the risk of fatigue damage at the rubber layer bonding area. The three continuously transitioning curved surfaces not only optimize the flow and fusion of the rubber compound during vulcanization, ensuring a tight fit between the upper and lower triangular rubber sections and effectively preventing quality issues such as interlayer delamination, but also reduce heat generation in the bead transition area during driving, thus improving fatigue resistance. It can significantly reduce flexural deformation and premature damage in the bead area, improve the tire's maximum load-bearing capacity, and extend its service life. It is especially suitable for all-steel radial truck tires and engineering machinery tires that have stringent requirements for load-bearing strength and durability. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the all-steel radial tire bead provided in an embodiment of the present invention; Figure 2 A schematic diagram of the geometric parameters of the all-steel radial tire bead provided in an embodiment of the present invention; Figure 3 This is a strain energy density cloud map of the soft triangular adhesive near the segmentation interface provided in an embodiment of the present invention; Figure 4 The strain energy density cloud map of the soft triangular adhesive near the segmentation interface is provided as a comparative example of the present invention.

[0018] Icons: 1-Bead wire; 2-Triangle rubber; 3-Carcass ply; 4-Sidewall rubber; 5-Lower triangle rubber; 6-Upper triangle rubber; 7-Curved surface; 8-First transition arc; 9-Second transition arc; 10-Third transition arc. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0024] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0026] Example 1 like Figure 1 , Figure 2 As shown, the all-steel radial tire bead provided by the present invention includes: a bead wire 1, a triangular rubber 2 covering the outside of the bead wire 1, a carcass ply layer 3 covering the outside of the triangular rubber 2, and the upper end of the triangular rubber 2 extending outward along the radial direction of the tire and smoothly transitioning to the sidewall rubber 4. The triangular adhesive 2 includes a lower triangular adhesive 5 and an upper triangular adhesive 6. The cross-section of the lower triangular adhesive 5 is a low triangular wedge shape. The upper triangular adhesive 6 is above the lower triangular adhesive 5. The transition interface between the lower triangular adhesive 5 and the upper triangular adhesive 6 forms an arc surface 7. The arc surface 7 includes a first transition arc 8, a second transition arc 9, and a third transition arc 10 that are sequentially connected on the radial section of the tire to form a continuous transition interface. The ratio of the height H1 at the top of the lower triangular adhesive 5 to the total height H of the triangular adhesive 2 is 0.3 to 0.5, preferably 0.35.

[0027] Specifically, the bead wire 1 is the supporting component of the bead of the all-steel radial tire, and its outer side is completely covered by the triangular rubber 2, forming a close-fitting covering structure. The outer side of the triangular rubber 2 is covered by the carcass ply 3, which is in contact with the outer surface of the triangular rubber 2. The upper end of the triangular rubber 2 extends outward along the radial direction of the tire, and is seamlessly connected with the sidewall rubber 4 through a smooth transition structure, ensuring continuous mechanical transmission between the bead and the sidewall. The triangular rubber 2 is a double-layer composite, including a lower triangular rubber 5 and an upper triangular rubber 6: the lower triangular rubber 5 is located at the bottom of the triangular rubber 2, and its cross-section is a low triangular wedge shape, with its lower end in close contact with the outer wall of the bead wire 1; the upper triangular rubber 6 is located directly above the lower triangular rubber 5, and its lower end face is in contact with the upper end face of the lower triangular rubber 5 through the curved surface 7. The curved surface 7 is the transition interface between the lower triangular rubber 5 and the upper triangular rubber 6. On the radial section of the tire, it is formed by the first transition arc 8, the second transition arc 9, and the third transition arc 10 connected end to end in sequence. The three arcs form a continuous segmentation interface without any bends. The second transition arc 9 is tangent to the first transition arc 8 and the third transition arc 10 respectively, ensuring a smooth transition of the interface geometry. At the same time, the height H1 of the highest point of the lower triangular rubber 5 and the total height H of the triangular rubber 2 satisfy a ratio of 0.3 to 0.5.

[0028] The arc surface 7, composed of the first transition arc 8, the second transition arc 9, and the third transition arc 10 in three continuous transition segments, abandons the traditional flat or simple inclined interface, avoiding abrupt changes in rubber properties at the interface. This significantly reduces local stress peaks and strain energy concentration at the joint between the lower triangular rubber 5 and the upper triangular rubber 6, effectively delaying fatigue damage and delamination risks at the interface. Simultaneously, this smooth transition facilitates the flow and fusion of the two rubber compounds during vulcanization, ensuring bonding quality at the interface. The low-profile triangular wedge-shaped lower triangular rubber 5, combined with a height ratio of 0.3–0.5 (H1 / H), concentrates the high-modulus hard rubber compound on the critical support area near the bead wire 1. This ensures the required support stiffness at the bead area, significantly reducing flexural deformation under high loads and shear stress at the reverse-wrapping end of the carcass ply, while also preventing excessive upward extension of the rigid rubber compound, which could lead to a decrease in sidewall flexibility.

[0029] Example 2 In Embodiment 2 of the present invention, the upper surface of the bead wire 1 is used as the height reference plane. The starting point of the first transition arc 8 is the highest point H1 of the lower triangular rubber 5, and the ending point of the first transition arc 8 is P1. The starting point of the third transition arc 10 is P2, and the ending point of the third transition arc 10 is the intersection of the bottom end of the lower triangular rubber 5 and the outline of the tire carcass ply 3. The ratio of the longitudinal length h1 of P1 to the top height H1 of the lower triangular rubber 5 is 0.3 to 0.4, and the lateral length d1 of P1 is the horizontal distance between P1 and the middle extension line of the bead wire 1. The ratio of the longitudinal length h2 of P2 to h1 is 0.2 to 0.3, and the lateral length d2 of P2 is the horizontal distance between P2 and the middle extension line of the bead wire 1.

[0030] The longitudinal length h1 of the endpoint P1 of the first transition arc 8 is 13-20 mm, and d1 is 2-5 mm; the longitudinal length h2 of the starting point P2 of the third transition arc 10 is 1 mm-5 mm, and d2 is 4-8 mm.

[0031] The radius of curvature of the first transition arc 8 ranges from 30 to 120 mm, the radius of curvature of the second transition arc 9 ranges from 5 to 30 mm, and the radius of curvature of the third transition arc 10 ranges from 2 to 12 mm.

[0032] One end of the second transition arc 9 is tangent to the first transition arc 8 at P1, and the other end of the second transition arc 9 is tangent to the third transition arc 10 at P2, thus achieving tangential continuity of the three arc segments.

[0033] Specifically, in this embodiment, the upper surface of the bead wire 1 is used as the height reference plane, and a local coordinate system is established along the radial direction outward of the tire as the height direction to clarify the positions of the three transition arcs. The highest point of the lower triangular rubber 5 is its top height H1, which also serves as the starting point of the first transition arc 8, and the end point of the first transition arc 8 is the feature point P1; the starting point of the third transition arc 10 is the feature point P2, and the end point is the intersection of the bottom end of the lower triangular rubber 5 and the outline of the tire carcass ply 3. The ratio of the longitudinal length h1 (height relative to the reference plane) of P1 to the height h1 of the top of the lower triangular rubber 5 is 0.3 to 0.4. The lateral length d1 is the horizontal distance between P1 and the middle extension line of the bead wire 1, and h1 is 13 to 20 mm and d1 is 2 to 5 mm. The ratio of the longitudinal length h2 (height relative to the reference plane) of P2 to h1 is 0.2 to 0.3. The lateral length d2 is the horizontal distance between P2 and the middle extension line of the bead wire 1, and h2 is 1 to 5 mm and d2 is 4 to 8 mm.

[0034] The radius of curvature of the first transition arc 8 is 30-120mm, the radius of curvature of the second transition arc 9 is 5-30mm, and the radius of curvature of the third transition arc 10 is 2-12mm. One end of the second transition arc 9 is tangent to the first transition arc 8 at P1, and the other end is tangent to the third transition arc 10 at P2, thus forming a three-segment arc transition structure without bends and with continuous tangential direction, connecting the interface between the lower triangular adhesive 5 and the upper triangular adhesive 6.

[0035] The constraints of P1 and P2 ensure that the contours of the three transition arcs can adapt to the low triangular wedge structure of the lower triangular rubber 5 and the contour of the carcass ply 3, avoiding stress concentration caused by dimensional misalignment. The curvature radius range of the three arcs covers the adaptation requirements of different tire specifications, effectively dispersing the local stress at the interface between the lower triangular rubber 5 and the upper triangular rubber 6, and reducing the risk of strain energy concentration. On the other hand, the longitudinal and lateral dimensions and proportion constraints of P1 and P2 not only ensure the support concentration of the high-modulus area of ​​the lower triangular rubber 5, but also make the stiffness gradually decrease from the lower triangular rubber 5 to the upper triangular rubber 6 through the arc transition, improving the flow and fusion effect of the rubber compound during vulcanization, avoiding interlayer delamination, enhancing the flexural deformation resistance of the bead area, reducing heat generation during driving, and significantly improving the tire's load-bearing capacity and durability reliability.

[0036] Example 3 In Embodiment 3 of the present invention, the height H1 of the top of the lower triangular adhesive 5 is 20-60 mm, and the total height H of the triangular adhesive 2 is 60-120 mm.

[0037] The height of the upper triangular glue 6 is the difference between the total height H of the triangular glue 2 and the height H1 of the top of the lower triangular glue 5.

[0038] The Shore A hardness of the lower triangular rubber 5 is 80-90, and the Shore A hardness of the upper triangular rubber 6 is 60-70.

[0039] Specifically, regarding the position of the triangular adhesive 2, the lower triangular adhesive 5 is located at the bottom of the triangular adhesive 2. The height H1 of the top of the lower triangular adhesive 5 ranges from 20 to 60 mm, and the total height H of the triangular adhesive 2 ranges from 60 to 120 mm. The height of the upper triangular adhesive 6 is the difference between the total height H of the triangular adhesive 2 and the height H1 of the top of the lower triangular adhesive 5, i.e., the height of the upper triangular adhesive 6 is H-H1. In terms of performance parameters, the Shore A hardness of the lower triangular adhesive 5 is 80-90, and the Shore A hardness of the upper triangular adhesive 6 is 60-70.

[0040] Through precise synergistic design of height ratio and hardness gradient, comprehensive performance optimization is achieved: the lower triangle rubber 5 adopts a height range of 20-60mm and a high hardness of 80-90 Shore A, which not only ensures the required support stiffness of the bead area and effectively resists flexural deformation near the bead wires under high load conditions, but also reduces shear stress at the reverse end of the carcass ply 3. Furthermore, because H1 is controlled at 1 / 3 to 1 / 2 of the total height H (H1 / H=0.30-0.50), it avoids the limitation of sidewall flexibility caused by excessive upward extension of rigid rubber. The upper triangle rubber 6 is highly compatible with the lower triangle rubber 5, and its low hardness of 60-70 Shore A gives it excellent flexibility and fatigue resistance, mitigating stress concentration in the transition area from the bead to the sidewall and reducing heat generation during driving. It takes into account both the load-bearing and support requirements of the tire and the driving comfort. Through the dual gradual change of hardness and height, it reduces the performance abrupt change of the rubber layer interface, delays fatigue damage and delamination risk, and significantly improves the durability of the triangular rubber 2 and the overall load-bearing capacity of the tire.

[0041] Example 4 In Embodiment 4 of the present invention, taking a 10.00R20 all-steel radial tire as an example, the total height H of the lower triangular rubber 2 is 98; the height H1 of the lower triangular rubber 5 is 35; and the height H2 of the upper triangular rubber 6 is 63 (H1 / H=0.357). Feature point parameters: h1=13.5, d1=2.8 at point P1; h2=3.6, d2=6.3 at point P2. Radius of the three arc segments: the first transition arc 8 is 56, the second transition arc 9 is 13, and the radius of the third transition arc is 4.

[0042] Comparative Example In this comparative example, taking the 10.00R20 all-steel radial tire as an example, the total height of triangle 2, the height of the lower triangle 5 and the upper triangle 6 are the same. The difference is that the junction is a straight line.

[0043] Comparing Example 4 with the comparative example, under the same load and the same boundary conditions, such as Figure 3 , Figure 4 As shown, a finite element method (FEM) comparative analysis was performed on the arc-shaped (three tangent circular arcs) segmentation interface scheme and the straight-line segmentation interface scheme. The strain energy density of elements in the upper triangular rubber 6 region near the segmentation interface was compared. In the arc-shaped segmentation interface scheme, the average strain energy density of the six elements in the upper triangular rubber 6 region near the interface was 0.1069; in the straight-line segmentation interface scheme, the average strain energy density of the five elements in the corresponding position was 0.1247. Using the straight-line segmentation interface as the benchmark, the average strain energy density of the arc-shaped segmentation interface scheme decreased by approximately 14.3%. This result indicates that the three tangent continuous segmentation interface design in Example 4 can reduce the local energy concentration of the soft triangular rubber near the interface, which is beneficial to improving the fatigue durability of the bead region.

[0044] In summary, the all-steel radial tire bead provided by this invention exhibits excellent performance improvements through laboratory simulation and whole-tire testing. Compared to the comparative example, with the same bead wire and ply configuration, the peak stress in the bead area of ​​Example 4 of this invention is reduced by approximately 20%, and dynamic compression heat generation is reduced by approximately 15%. Tire load capacity testing shows that bead deformation is significantly reduced, and the maximum tire load capacity is increased by approximately 8% to 10%. In tire durability tests, the tire using the structure of this invention did not show early delamination, cracks, or other damage in the bead area under simulated overload and long-term operating conditions, while the conventional structure bead in the comparative example often showed micro-cracks or signs of rubber layer separation near the inverted end of the tire carcass. Therefore, it is fully demonstrated that the double-layer triangular rubber structure of this invention effectively improves the durability of the bead area, enabling the tire to have a longer service life and higher reliability under heavy-load conditions.

[0045] Based on the above embodiments, the specific manufacturing method of the all-steel radial tire bead provided by the present invention is as follows: The triangular rubber 2 in the bead of the all-steel radial tire of the present invention can be formed in one step by co-extrusion. Using an extrusion device with a composite extruder head, two rubber compounds are fed and plasticized into two screws respectively, and then combined and extruded at the die head. Through a specially designed die, a triangular rubber strip containing upper and lower layers of rubber with a desired arc-shaped transition cross-section can be extruded simultaneously. After extrusion, the composite triangular rubber strip is cut to a certain length and attached to the periphery of the bead wire 1. During the forming process, the lower triangular rubber 5 and the upper triangular rubber 6 are pre-bonded; subsequently, during tire vulcanization, the two rubber compounds vulcanize simultaneously, achieving cross-linking and fusion of molecular chains at the interface, ultimately forming a robust, integrated triangular rubber structure.

[0046] In addition, if co-extrusion is not feasible due to equipment or process limitations, a step-by-step bonding method can be used. In this method, the lower triangular rubber strip 5 is first extruded separately and accurately attached to the bead wire 1, maintaining its upper surface in a predetermined arc shape. Then, the upper triangular rubber strip 6 is extruded and attached to the lower triangular rubber strip 5, creating a rounded transition at the interface between the upper and lower strips. To ensure a tight bond, appropriate rolling pressure can be applied to the upper triangular rubber strip 6 during the bonding process to align it with the arc surface of the lower strip. Finally, during vulcanization, the lower triangular rubber strip 5 and the upper triangular rubber strip 6 will vulcanize simultaneously and bond firmly together, forming an integrated structure with the same effect as the co-extrusion process.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bead for an all-steel radial tire, comprising: The tire has a bead wire (1), the bead wire (1) is covered with a triangular rubber (2) on the outside, the triangular rubber (2) is covered with a tire carcass ply (3), and the upper end of the triangular rubber (2) extends outward along the radial direction of the tire and smoothly transitions to the sidewall rubber (4). The tire is characterized by... The triangular adhesive (2) includes a lower triangular adhesive (5) and an upper triangular adhesive (6). The lower triangular adhesive (5) has a low triangular wedge-shaped cross section. The upper triangular adhesive (6) is located above the lower triangular adhesive (5). The transition interface between the lower triangular adhesive (5) and the upper triangular adhesive (6) forms an arc surface (7). The arc surface (7) includes a first transition arc (8), a second transition arc (9), and a third transition arc (10) that are connected sequentially on the radial section of the tire to form a continuous transition interface. The height H1 of the top of the lower triangular adhesive (5) is 0.3 to 0.5 of the total height H of the triangular adhesive (2).

2. The all-steel radial tire bead according to claim 1, characterized in that, With the upper surface of the bead wire (1) as the height reference plane, the starting point of the first transition arc (8) is the highest point H1 of the lower triangular rubber (5), and the ending point of the first transition arc (8) is P1; the starting point of the third transition arc (10) is P2, and the ending point of the third transition arc (10) is the intersection of the bottom end of the lower triangular rubber (5) and the outline of the carcass ply (3). Wherein, the ratio of the longitudinal length h1 of P1 to the height H1 of the top of the lower triangular rubber (5) is 0.3 to 0.4, and the lateral length d1 of P1 is the horizontal distance between P1 and the middle extension line of the bead wire (1); the ratio of the longitudinal length h2 of P2 to h1 is 0.2 to 0.3, and the lateral length d2 of P2 is the horizontal distance between P2 and the middle extension line of the bead wire (1).

3. The all-steel radial tire bead according to claim 2, characterized in that, The longitudinal length h1 of the end point P1 of the first transition arc (8) is 13-20 mm and d1 is 2-5 mm; the longitudinal length h2 of the starting point P2 of the third transition arc (10) is 1 mm-5 mm and d2 is 4-8 mm.

4. The all-steel radial tire bead according to claim 2, characterized in that, The radius of curvature of the first transition arc (8) is in the range of 30 to 120 mm, the radius of curvature of the second transition arc (9) is in the range of 5 to 30 mm, and the radius of curvature of the third transition arc (10) is in the range of 2 to 12 mm.

5. The all-steel radial tire bead according to claim 2, characterized in that, One end of the second transition arc (9) is tangent to the first transition arc (8) at P1, and the other end of the second transition arc (9) is tangent to the third transition arc (10) at P2, thus achieving tangential continuity of the three arc segments.

6. The all-steel radial tire bead according to claim 1, characterized in that, The height H1 of the top of the lower triangular adhesive (5) is 20-60mm, and the total height H of the triangular adhesive (2) is 60-120mm.

7. The all-steel radial tire bead according to claim 6, characterized in that, The height of the upper triangular adhesive (6) is the difference between the total height H of the triangular adhesive (2) and the height H1 of the top of the lower triangular adhesive (5).

8. The all-steel radial tire bead according to claim 1, characterized in that, The lower triangular adhesive (5) has a Shore A hardness of 80-90, and the upper triangular adhesive (6) has a Shore A hardness of 60-70.

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