A pneumatic tire with a triangular rubber structure of gradually varying hardness

Abstract

This invention discloses a pneumatic tire with a gradually increasing hardness triangular rubber structure, comprising a first triangular rubber disposed radially outside the steel wire bead; and a second triangular rubber disposed radially outside the first triangular rubber. The elastic modulus of the first triangular rubber is greater than that of the second triangular rubber. The interface between the second and first triangular rubbers is a curve ab, which bulges towards the first triangular rubber. The point of maximum curvature of curve ab is vertex c, and the position of vertex c satisfies: H5-H4 = 5-15mm; h2 / h1 = 0.3-0.5. This invention optimizes the axial thickness variation trend of the first and second triangular rubbers by constraining the axial and radial positions of vertex c in curve ab, resulting in a uniform increase in hardness of the bead from the left endpoint a to vertex c to the right endpoint b. This improves the load-bearing capacity of the bead and sidewall, increases the degree of bending deformation of both, reduces stress concentration at curve ab, and improves tire durability.

Description

Technical Field

[0001] This utility model relates to the field of pneumatic tire technology, specifically to a pneumatic tire with a triangular rubber structure having gradually varying hardness. Background Technology

[0002] As the only part of a vehicle in contact with the ground, the durability of tires directly affects driving safety, fuel economy, and service life. Under complex road conditions and long-term loads, fatigue failure in the bead area (including the triangular rubber compound) is one of the main manifestations of insufficient tire durability, easily leading to problems such as bead delamination and bulges. The triangular rubber compound, located in the tire bead area, performs the following core functions: first, mechanical support, dispersing stress in the bead area through high-hardness rubber material, preventing the ply layer from separating from the steel wire due to excessive deformation; second, buffering, absorbing the impact load on the contact area between the bead and the rim during driving, reducing local strain. However, existing tire triangular rubber compound designs have the following problems: single-hardness rubber materials easily cause stress concentration. For example, while high-hardness rubber materials enhance support, they exacerbate bead flexing fatigue, while low-hardness rubber materials may lead to uncontrolled tire deformation. Traditional designs combine high-hardness and low-hardness rubber materials, but the quantitative relationship between the shape of the boundary between the two and durability is unclear, and reliance on experience-based design leads to low optimization efficiency.

[0003] As can be seen from the published Chinese patent CN107471923A, the solid line BBL represents the bead baseline, which is a line that specifies the diameter of the rim to which the tire fits; as can be seen from the published Chinese patent CN119408349A, the tire section width SW is common knowledge in the field; the sidewall deformation zone is located in the sidewall area with less rubber, and its maximum axial width is the tire section width SW.

[0004] The published Chinese patent CN107471923A for pneumatic tires discloses that the ratio of the height L4 from the outer end of the cross-sectional arrangement of the wire to the inner end of the second triangular rubber to the width WC of the bead core (L4 / WC) is 0.4 or more and 0.9 or less, and that the straight line connecting the two ends of the contact portion of the first and second triangular rubbers is designated as LA, and the ratio of the depth DA of the recess based on the straight line LA to the width WC (DA / WC) is 0.2 or more and 0.5 or less. The above technical features roughly limit the shape of the interface of triangular rubbers with different hardness, but do not specifically describe the shape of the combination of triangular rubbers with different hardness, thus failing to clarify the quantitative relationship of the rigidity transition of the combination of triangular rubbers with different hardness, and therefore failing to improve the tire durability by improving the shape of the combination of triangular rubbers with different hardness. Utility Model Content

[0005] This invention aims to improve the rigidity transition of triangular rubber components with different hardness, providing a pneumatic tire with a triangular rubber structure of gradually varying hardness. The specific technical solution is as follows:

[0006] A pneumatic tire with a triangular rubber structure of gradually varying hardness includes: a tire body and a bead. The tire body includes a main portion disposed axially inside the bead and a reverse-wrapped portion axially outside the bead. The bead includes a steel wire ring disposed at the end. The bead also includes: a first triangular rubber disposed radially outside the steel wire ring; and a second triangular rubber disposed radially outside the first triangular rubber. The elastic modulus of the first triangular rubber is greater than that of the second triangular rubber. The interface between the second and first triangular rubbers is a curve ab, which bulges towards the first triangular rubber. The point with the maximum curvature of curve ab is vertex c. The radial distance between vertex c and the bead baseline BL is H5. The radial distance between the right endpoint b of the second triangular rubber and the bead baseline BL is H4. The axial distance between vertex c and the main portion is h2. The axial thickness of the first and second triangular rubbers at vertex c is h1. The position of vertex c satisfies: H5-H4=5~15mm; h2 / h1=0.3~0.5.

[0007] Furthermore, the cross-section of the wire ring is an equiangular hexagon, and the wire ring forms a side surface A with an inclination angle of 15°. The extension line of side surface A intersects the reverse wrapping part at the intersection point q. The radial distance between the intersection point q and the tire bead baseline BL is H8, and H8 is a fixed value. The intersection point of curve ab and the reverse wrapping part is the right endpoint b. The radial distance between the right endpoint b and the tire bead baseline BL is H4, -5mm≤H8-H4≤5mm; H5-H4=h, and the radial distance between the vertex c and the right endpoint b is h.

[0008] Furthermore, the wire loop is set in the area enclosed by the main part and the reverse wrapping part, and the minimum distance between the outer side of the wire loop and the right end point b is h4; the minimum distance between the outer side of the wire loop and the curve ab is h3, and h3≥h4.

[0009] Preferably, the radial outer side of the second triangular rubber is close to the tire crown, and the distance between the upper end point of the axial outer side of the second triangular rubber and the bead baseline BL is H1; the radial distance between the mold tire section width SW and the bead baseline BL is LSH, satisfying: H1 / LSH=0.7~0.9.

[0010] Preferably, the radial distance between the axial outer end point f of the reverse wrapping part and the bead baseline BL is H2, satisfying: H2 / LSH=0.3~0.5.

[0011] Preferably, curve ab intersects the main part at the left endpoint a, the left endpoint a is the upper inner axial endpoint a of the first triangular rubber, and the radial distance between the upper inner axial endpoint a and the bead baseline BL is H3, H3 / H2 = 1~1.4.

[0012] Preferably, it also includes a steel cord fabric disposed on the outer side of the tire body, wherein the distance between the outer axial end point e of the steel cord fabric and the outer axial end point f of the reverse wrapping part is H6, where H6 = 10~16mm.

[0013] Preferably, the outer axial end point f of the reverse wrapping part is projected onto the projection point p along the vertical line perpendicular to the main part, and the distance between the projection point p and the inner axial end point g of the steel wire curtain is H7, where H7 = -10 to 10 mm.

[0014] Preferably, the elastic modulus of the first triangular rubber is E1, E1 = 12~15 MPa; and the elastic modulus of the second triangular rubber is E2, E2 = 3~6 MPa.

[0015] As can be seen from the above technical solution, this utility model has the following beneficial effects:

[0016] This invention optimizes the axial thickness variation trend of the first and second triangular rubbers by constraining the axial and radial positions of the vertex c in curve ab. This results in a uniform increase in the hardness of the tire bead from the left end a to the vertex c to the right end b, thereby improving the load-bearing capacity of the tire bead and sidewall, increasing the degree of bending deformation of both, reducing stress concentration at curve ab, and improving tire durability. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of a portion of the pneumatic tire involved in an embodiment of the present utility model;

[0018] Figure 2 for Figure 1 Enlarged view of the structure at point A in the image.

[0019] In the diagram: 1. Sidewall; 2. Bead; 21. First triangle rubber; 22. Second triangle rubber; 23. Bead wire; 3. Carcass; 31. Main body; 32. Reverse wrapping part; 4. Cord wire. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] In the description of the embodiments of this utility model, it should be noted that the terms "inner", "outer", "upper", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the utility model product is usually placed when in use. They are only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model.

[0022] like Figure 1 As shown, in this embodiment, up, down, left, and right represent the radial outer side, radial inner side, axial inner side, and axial outer side, respectively.

[0023] Furthermore, a pneumatic tire with a triangular rubber structure of gradually varying hardness includes: a tire body 3 and a tire bead 2. The tire body 3 includes a main portion 31 disposed on the inner side of the tire bead 2 and a reverse wrap portion 32 disposed on the outer side of the tire bead 2. The tire bead 2 includes a steel wire ring 23 disposed at the end.

[0024] As is known from common knowledge in the field, a pneumatic tire includes a crown, a sidewall 1, a body 3, and a bead 2. The body 3 is located on the inner side of the crown and sidewall 1 as the main part 31, and the two ends of the body 3 that wrap around to the outer side of the sidewall 1 are called the wrapping parts 32. The bead 2 is located on the inner side of the part where the main part 31 transitions to the wrapping parts 32. In this embodiment, the bead 2 includes a wire loop 23 located at the end of the body 3. The cross-section of the wire loop 23 is an equiangular hexagon, and the positional relationship between its six sides and the body 3 is relatively fixed. The four sides are in contact with the inner side of the body 3, providing it with support.

[0025] like Figure 2 As shown, the side of the wire ring 23 facing the main part 31 is called side A, and the side facing the reverse wrapping part 32 is called side B. The tilt angle of side A is 15°, and the tilt angle of side B is 135°. The reference line for measuring the angle is a straight line parallel to the axis. This tilt angle is the detection value during the production process of the pneumatic tire in this embodiment. Therefore, the position of the wire ring 23 relative to the tire bead 2 is determined. When the diameter of the wire ring 23 is determined, the position of the intersection point q where the extension line of side A intersects with the reverse wrapping part 32 can be determined according to the position of the wire ring 23, and then H8 is determined.

[0026] Furthermore, the bead 2 also includes: a first triangular rubber 21 disposed radially outside the wire bead 23; and a second triangular rubber 22 disposed radially outside the first triangular rubber 21. The elastic modulus of the first triangular rubber 21 is greater than that of the second triangular rubber 22. The interface between the second triangular rubber 22 and the first triangular rubber 21 is a curve ab, which bulges toward the first triangular rubber 21. The point with the maximum curvature of the curve ab is vertex c. The radial distance between vertex c and the bead baseline BL is H5. The radial distance between the right end point b of the second triangular rubber 22 and the bead baseline BL is H4. The axial distance between vertex c and the main part 31 is h2. The axial thickness of the first triangular rubber 21 and the second triangular rubber 22 at vertex c is h1. The position of vertex c satisfies: H5-H4=5~15mm; h2 / h1=0.3~0.5.

[0027] Specifically, the left side of the first triangular rubber 21 coincides with the inner side of the main part 31, the bottom side of the first triangular rubber 21 coincides with the top side of the wire bead 23, the top side of the first triangular rubber 21 coincides with the bottom side of the second triangular rubber 22, and the right side of the first triangular rubber 21 coincides with the inner side of the reverse wrapping part 32. The length of the left side of the first triangular rubber 21 is greater than the length of the right side of the first triangular rubber 21, thus forming a trapezoidal shape. The left side of the second triangular rubber 22 coincides with the inner side of the main part 31, and the right side of the second triangular rubber 22 coincides with the inner side of the reverse wrapping part 32, thus forming a triangular shape. This makes the hardness of the tire sidewall 1 and the tire bead 2 increase from the radially outer side to the radially inner side, thereby ensuring the cushioning performance and load-bearing performance of the tire sidewall 1.

[0028] Secondly, the top edge of the first triangular rubber 21 is a curve ab, which protrudes towards the first triangular rubber 21. Its two ends intersect with the main part 31 and the reverse wrapping part 32 respectively. As the curve ab moves from the left endpoint a to the vertex c, its curvature gradually increases. As the curve ab moves from the vertex c to the right endpoint b, its curvature gradually decreases. This causes the elastic modulus of the bead 2 to gradually increase from the left endpoint a to the right endpoint b, that is, the hardness of the bead 2 gradually increases. Moreover, the increase is non-linear, which improves the distribution of the hardness of the bead 2, thereby reducing the stress concentration during the bending process of the sidewall 1 and improving the service life of the tire.

[0029] Secondly, H5-H4 represents the radial distance between vertex c and right endpoint b, which reflects the hardness transition between the first triangular rubber 21 and the second triangular rubber 22. When H5-H4 < 5mm, the axial thickness of the first triangular rubber 21 increases too rapidly from vertex c to right endpoint b, causing the hardness of the bead 2 to increase too rapidly from vertex c to right endpoint b. This increases stress concentration at curve cb, making it easier for the first triangular rubber 21 and the second triangular rubber 22 to separate, thus reducing the service life of the bead 2. When H5-H4 > 15mm, the axial thickness of the first triangular rubber 21 increases too slowly from vertex c to right endpoint b, causing the hardness of the bead 2 to increase too slowly from vertex c to right endpoint b. This reduces the load-bearing capacity at curve cb, thus reducing the load-bearing capacity of the bead 2, increasing its bending deformation, and thus reducing its fatigue strength and service life.

[0030] Secondly, h2 / h1 represents the distance from vertex c to the inner side of the main part 31. The axial distance between vertex c and the left endpoint a is proportional to it. When h2 / h1 increases, vertex c moves away from the left endpoint a, and when h2 / h1 decreases, vertex c moves closer to the left endpoint a. When h2 / h1 < 0.3, the axial thickness of the second triangular rubber 22 from the left endpoint a to vertex c increases too quickly, causing the hardness of the bead 2 from the left endpoint a to vertex c to increase too slowly. This reduces the load-bearing capacity at curve ac, thus reducing the load-bearing capacity of the bead 2, increasing its bending deformation, and thus reducing its fatigue strength and service life. When h2 / h1 > 0.5, the axial thickness of the second triangular rubber 22 from the left endpoint a to vertex c increases too slowly, causing the hardness of the bead 2 from the left endpoint a to vertex c to increase too quickly. This increases the stress concentration at curve ac, which can easily cause the first triangular rubber 21 and the second triangular rubber 22 to separate, reducing the service life of the bead 2.

[0031] Furthermore, the cross-section of the wire ring 23 is an equiangular hexagon, and the wire ring 23 forms a side surface A with an inclination angle of 15°. The extension line of side surface A intersects the reverse wrapping part 32 at the intersection point q. The radial distance between the intersection point q and the bead baseline BL is H8, where H8 is a fixed value. The intersection point of the curve ab and the reverse wrapping part 32 is the right endpoint b. The radial distance between the right endpoint b and the bead baseline BL is H4, where -5mm ≤ H8 - H4 ≤ 5mm; H5 - H4 = h, and the radial distance between the vertex c and the right endpoint b is h.

[0032] Specifically, as described above, in this embodiment, side A is fixed relative to bead 2 and has only one relative position. Therefore, H8 is a known dimension in this embodiment. H8-H4 represents the distance between the intersection point q and the right end point b. When H8-H4 is less than -5mm or greater than 5mm, the distance between the intersection point q and the right end point b is too large. This causes the side B of the wire ring to be unable to provide sufficient support when the first triangular rubber bends and deforms. Consequently, the hardness of the second triangular rubber changes unevenly during the transition from the first triangular rubber to the side B of the wire ring, thereby increasing the fatigue limit of the first and second triangular rubbers and reducing the durability of the bead.

[0033] From H4+5≤H5≤H4+15mm, we can know the specific range of H5, and then determine the radial position of vertex c relative to the bead baseline BL.

[0034] like Figure 2 As shown, the wire loop 23 is disposed in the area surrounded by the main part 31 and the reverse wrapping part 32. The minimum distance between the outer side of the wire loop 23 and the right end point b is h4; the minimum distance between the outer side of the wire loop 23 and the curve ab is h3, and h3≥h4.

[0035] Specifically, a portion of the side surface of the steel wire ring 23 overlaps with the inner surface of the main portion 31 and the inner surface of the reverse wrap portion 32 to provide support for the tire carcass 3, thereby providing support for the part of the tire that contacts the rim and improving the tire's durability. Secondly, the distance between the side surface B of the steel wire ring 23 and the right endpoint b is h4, and the shortest distance between the side surface B of the steel wire ring 23 and the curve ab is h3, where h3 represents the distance between the bottom edge of the second triangular rubber 22 and the steel wire ring 23. When h3 < h4, the curvature of curve cb changes as follows: gradually decreasing, then gradually increasing, then gradually decreasing again. The distance between the maximum curvature point of curve cb and side B is less than h4, which is h3. At this time, the distance between the bottom edge of the second triangular rubber 22 and side B changes from the inner side to the outer side of the axial direction as follows: gradually decreasing, then gradually increasing. This makes the hardness transition of the second triangular rubber 22 and the first triangular rubber 21 uneven, which in turn intensifies the stress concentration in the right end point b region. Consequently, the first triangular rubber 21 or the second triangular rubber 22 is prone to separation from the tire body 3, reducing the tire's durability.

[0036] Furthermore, the radial outer side of the second triangular rubber 22 is closer to the tire crown, and the distance between the upper end point m of the axial outer side of the second triangular rubber 22 and the bead baseline BL is H1; the radial distance between the tire section width SW and the bead baseline BL is LSH, satisfying: H1 / LSH=0.7~0.9.

[0037] Specifically, LSH is a value determined in this embodiment, H1-H4 are the lengths of the second triangular rubber 22 along the outer surface of the sidewall 1, and H4 is a determined value. Therefore, H1 represents the length of the second triangular rubber 22 along the outer surface of the sidewall 1, and H1 / LSH represents the distance from the upper axially outer end point m of the second triangular rubber 22 to the deformation zone of the sidewall 1, where the upper axially outer end point m is the vertex m. When H1 / LSH < 0.7, the vertex m of the second triangular rubber 22 is too far from the deformation zone of the sidewall 1, which reduces the bending strength of the sidewall 1, making it prone to fatigue damage, reducing its load-bearing capacity, and thus reducing its durability. When H1 / LSH > 0.9, the vertex m of the second triangular rubber 22 is too close to the deformation zone of the sidewall 1, which increases the bending strength of the deformation zone near the second triangular rubber 22, making the bending strength of the deformation zone uneven, which intensifies the stress concentration at the vertex m, making the second triangular rubber 22 at the vertex m prone to separating from the sidewall 1, reducing the service life of the sidewall 1.

[0038] Furthermore, the radial distance between the outermost axial end point f of the reverse wrapping part 32 and the bead baseline BL is H2, which satisfies: H2 / LSH=0.3~0.5.

[0039] Specifically, H2 / LSH represents the distance between the outermost axial endpoint f and the rightmost endpoint b along the outer sidewall 1. When H2 / LSH < 0.3, the distance between the outermost axial endpoint f and the rightmost endpoint b is too close, resulting in insufficient contact between the inner side of the reverse-wrap portion 32 and the right side of the second triangular rubber 22. Consequently, the reverse-wrap portion 32 cannot provide sufficient support for the second triangular rubber 22, leading to increased deformation of the second triangular rubber 22 under tire load, which in turn makes it prone to fatigue limit. Furthermore, the distance between the outermost axial endpoint f and the top edge of the first triangular rubber 21 is too close, resulting in increased stress concentration at the rightmost endpoint b.

[0040] Furthermore, curve ab intersects with main part 31 at left endpoint a, left endpoint a is the upper inner axial endpoint a of the first triangular rubber 21, and the radial distance between the upper inner axial endpoint a and the bead baseline BL is H3, H3 / H2 = 1~1.4.

[0041] Specifically, H2 / LSH represents the distance between the outermost axial endpoint f and the right endpoint b along the outer side of the tire sidewall 1, with LSH being a fixed value. H3 / H2 represents the radial height relationship between the left endpoint a and the outermost axial endpoint f, which can represent the radial distance relationship between the left endpoint a and the right endpoint b.

[0042] When H3 / H2 < 1, the left endpoint a is lower than the axial outer endpoint f, resulting in a larger contact area between the second triangular rubber 22 and the main part 31 compared to the first triangular rubber 21. This leads to a greater bending amplitude of the second triangular rubber 22 during the bending process of the sidewall 1, making it easier for it to reach its fatigue limit. The small distance between the left endpoint a and the right endpoint b reduces the torque generated by the pressure on the first triangular rubber 21 during the bending process of the sidewall 1, making it difficult to deform. This further exacerbates the stress concentration at the left endpoint a, causing the first triangular rubber... The first triangular rubber 21 and the second triangular rubber 22 are easily separated, reducing the service life of the tire. When H3 / H2>1.4, the left end point a is higher than the outer end point f of the axial direction, but too close to the vertex m of the second triangular rubber 22, making the contact area between the second triangular rubber 22 and the main part 31 too small. The contact area between the first triangular rubber 21 and the main part 31 is too large, which increases the overall hardness of the tire sidewall 1, reduces its bending performance, and reduces the tire's cushioning performance. At the same time, the left end point a is too close to the deformation area of ​​the tire sidewall 1, making the bending force it is subjected to too large, which in turn aggravates the stress concentration at the left end point a.

[0043] Furthermore, it also includes a steel cord fabric 4 disposed on the outer side of the tire body 3, the distance between the outermost axial end point e of the steel cord fabric 4 and the outermost axial end point f of the reverse wrapping part 32 is H6, H6 = 10~16mm.

[0044] Specifically, the steel cord fabric 4 is a key skeleton material of the tire. It is made of high-strength steel cord through a calendering process and coated with rubber. It is used in the tire carcass 3 to withstand the huge pressure, impact load and vibration during tire operation, ensuring the tire's strength, durability and stability. H6 represents the distance between the outermost axial end point e of the steel cord fabric 4 and the outermost axial end point f of the reverse wrapping part 32 along the surface of the tire sidewall 1. When H6 is less than 10mm, the outermost axial end point e of the steel cord fabric 4 and the outermost axial end point f of the reverse wrapping part 32 are too close. This causes increased heat generation and stress concentration in the ef area during bending of the tire sidewall 1, making the rubber properties in this area of ​​the tire sidewall 1 more susceptible to heat degradation, and making the steel cord fabric 4 and the reverse wrapping part 32 more prone to separation from the rubber, thus reducing the service life of the tire sidewall 1.

[0045] Furthermore, the outer axial end point f of the reverse wrapping part 32 is projected onto the projection point p along the vertical line perpendicular to the main part 31. The distance between the projection point p and the inner axial end point g of the steel wire curtain 4 is H7, where H7 = -10 to 10 mm.

[0046] Specifically, the distance between the outermost axial endpoint f and the bead baseline BL is determined, and H7 represents the proximity between the innermost axial endpoint g and the bead baseline BL, and the deformation zone of sidewall 1. When H7 < -10mm, the projection point p is lower than the innermost axial endpoint g, and the innermost axial endpoint g is too close to the deformation zone of sidewall 1. This results in excessive deformation of the innermost axial endpoint g when sidewall 1 is subjected to bending deformation, which intensifies stress concentration at this point and easily causes the steel cord 4 to separate from the inner surface of the main body 31 of the tire carcass 3, reducing tire life. When H7 > 10mm, the projection point p is higher than the innermost axial endpoint g, and the innermost axial endpoint g is too close to the steel wire bead 23. This results in insufficient contact area between the steel cord 4 and the main body 31, reducing the support effect on the main body 31, thus reducing the load-bearing capacity of sidewall 1 / bead 2, and consequently reducing the tire's load-bearing capacity.

[0047] Furthermore, the elastic modulus of the first triangular rubber 21 is E1, E1 = 12~15 MPa; the elastic modulus of the second triangular rubber 22 is E2, E2 = 3~6 MPa.

[0048] Specifically, the elastic modulus of the first triangular rubber 21 is greater than that of the second triangular rubber 22. When the elastic modulus E1 < 12 MPa, the supporting performance of the first triangular rubber 21 on the steel wire ring 23 is reduced, and the tire is prone to detaching from the rim. When the elastic modulus E1 > 15 MPa, the hardness of the first triangular rubber 21 is too high, making it difficult to bend and deform, which intensifies the stress concentration at curve ab, easily causing the first triangular rubber 21 to separate from the second triangular rubber 22. When the elastic modulus E2 < 2 MPa, the second triangular rubber 22 is easy to bend and deform, reducing its load-bearing capacity, and thus reducing the load-bearing capacity of the sidewall 1. When the elastic modulus E2 > 6 MPa, the hardness of the second triangular rubber 22 is too high, making it difficult for the second triangular rubber 22 to bend and deform during the bending process of the sidewall 1, which intensifies the stress concentration at the interface between it and the sidewall 1 rubber, making the second triangular rubber 22 easy to separate from the sidewall 1 rubber. Among these, the hardness of the second triangular rubber 22 is higher than the hardness of the sidewall rubber.

[0049] In this invention, unless otherwise specified, the dimensions and angles of the tire components are measured with the tire assembled on a standard rim and filled with air to achieve the standard internal pressure. No load is applied to the tire during measurement.

[0050]

Example

[0051] The effects of this utility model are explained below with reference to the embodiments, but this utility model should not be interpreted in a limiting way based on the implementation of these embodiments.

[0052] Comparative Example 1 uses a 12R22.5 18PR 152 / 149M truck tire for bead 2 durability testing. The test method is as follows: speed 30 km / h; load: maximum load of a single tire * 250% * 0.85 kg; ambient temperature 25±3℃. Each stage lasts 24 hours, with a 15-minute stop at the end of each stage. Individual tires are tested, and the time until damage to part 1 of the sidewall is measured. The results are expressed using an index with Comparative Example 1 set to 100, and are shown in Tables 1 to 7 below. Higher values ​​are better.

[0053] Table 1

[0054] Table 1 Evaluation Results

[0055]

[0056] H4 represents H8-H4=0, meaning the intersection point q coincides with the right endpoint b.

[0057] Table 2

[0058] Table 2 Evaluation Results

[0059]

[0060] Table 3

[0061] Table 3 Evaluation Results

[0062]

[0063] Table 4

[0064] Table 4 Evaluation Results

[0065]

[0066] Table 5

[0067] Table 5 Evaluation Results

[0068]

[0069] Table 6

[0070] Table 6 Evaluation Results

[0071]

[0072] Table 7

[0073] Table 7 Evaluation Results

[0074]

[0075] As shown in Tables 1 to 7, the preferred embodiments of this utility model are as follows:

[0076] A pneumatic tire with a gradually hardening triangular rubber structure includes: a tire body 3 and a bead 2. The tire body 3 includes a main portion 31 disposed axially inside the bead 2 and a reverse-wrapping portion 32 disposed axially outside the bead 2. The bead 2 includes a steel wire ring 23 disposed at its end. The bead 2 further includes: a first triangular rubber 21 disposed radially outside the steel wire ring 23; and a second triangular rubber 22 disposed radially outside the first triangular rubber 21. The elastic modulus of the first triangular rubber 21 is greater than that of the second triangular rubber 22. The second triangular rubber 22 and the first triangular rubber 21 have different elastic moduli. The interface is curve ab, which bulges toward the first triangular rubber 21. The point with the greatest curvature of curve ab is vertex c. The radial distance between vertex c and the bead baseline BL is H5. The radial distance between the right end point b of the second triangular rubber 22 and the bead baseline BL is H4. The axial distance between vertex c and the main part 31 is h2. The axial thickness of the first triangular rubber 21 and the second triangular rubber 22 at vertex c is h1. H5 = H4 + h. The radial distance between vertex c and the right end point b is h. h = 10 mm. h2 / h1 = 0.4.

[0077] Furthermore, the cross-section of the wire ring 23 is an equiangular hexagon, and the wire ring 23 forms a side surface A with an inclination angle of 15°. The extension line of the side surface A intersects the reverse wrapping part 32 at the right end point b. The radial distance between the right end point b and the bead baseline BL is H4, and H4 is a fixed value.

[0078] Furthermore, the wire loop 23 is disposed in the area surrounded by the main part 31 and the reverse wrapping part 32, and the minimum distance between the outer surface of the wire loop 23 and the right end point b is h4; the minimum distance between the outer surface of the wire loop 23 and the curve ab is h3, h3 = h4.

[0079] Preferably, the radial outer side of the second triangular rubber 22 is close to the tire crown, and the distance between the upper end point of the axial outer side of the second triangular rubber 22 and the tire bead baseline BL is H1; the radial distance between the mold tire section width SW and the tire bead baseline BL is LSH, satisfying: H1 / LSH=0.8.

[0080] Preferably, the radial distance between the outermost end point f of the reverse wrapping portion 32 and the bead baseline BL is H2, satisfying: H2 / LSH=0.4.

[0081] Preferably, curve ab intersects the main part 31 at the left end point a, the left end point a is the upper inner axial end point a of the first triangular rubber 21, and the radial distance between the upper inner axial end point a and the bead baseline BL is H3, H3 / H2=1.2.

[0082] Preferably, it also includes a steel wire cord 4 disposed on the outer side of the tire body 3, wherein the distance between the outer axial end point e of the steel wire cord 4 and the outer axial end point f of the reverse wrapping part 32 is H6, and H6 = 13 mm.

[0083] Preferably, the outer axial end point f of the reverse wrapping part 32 is projected onto the projection point p along the vertical line perpendicular to the main part 31, and the distance between the projection point p and the inner axial end point g of the steel wire curtain 4 is H7, where H7 = 0 mm.

[0084] Preferably, the elastic modulus of the first triangular rubber 21 is E1, E1 = 13.5 MPa; and the elastic modulus of the second triangular rubber 22 is E2, E2 = 4.5 MPa.

[0085] Although embodiments of the present 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 present invention, the scope of which is defined by the appended claims and their equivalents.

[0086] The technologies, shapes, and structures not described in detail in this utility model are all known technologies.

Claims

1. A pneumatic tire having a graduated durometer bead filler structure, comprising: The tire body (3) and the bead (2), wherein the tire body (3) includes a main portion (31) disposed on the axial inner side of the bead (2) and a reverse wrapping portion (32) disposed on the axial outer side of the bead (2), and the bead (2) includes a wire loop (23) disposed at the end, characterized in that the bead (2) further includes: The first triangular rubber (21) is disposed on the radially outer side of the wire ring (23); A second triangular rubber (22) is disposed radially outside the first triangular rubber (21). The elastic modulus of the first triangular rubber (21) is greater than that of the second triangular rubber (22). The interface between the second triangular rubber (22) and the first triangular rubber (21) is a curve ab. The curve ab bulges toward the first triangular rubber (21). The point with the largest curvature of the curve ab is vertex c. The radial distance between vertex c and the bead baseline BL is H5. The radial distance between the right end point b of the second triangular rubber (22) and the bead baseline BL is H4. The axial distance between vertex c and the main part (31) is h2. The axial thickness of the first triangular rubber (21) and the second triangular rubber (22) at vertex c is h1. The position of vertex c satisfies: H5-H4 = 5~15mm; h2 / h1 = 0.3 to 0.

5.

2. The pneumatic tire of claim 1, wherein: The cross-section of the wire ring (23) is an equiangular hexagon. The wire ring (23) forms a side surface A with an inclination angle of 15°. The extension line of the side surface A intersects the reverse wrapping part (32) at the intersection point q. The radial distance between the intersection point q and the tire bead baseline BL is H8, where H8 is a fixed value. The intersection of curve ab and the reverse wrapping part (32) is the right endpoint b. The radial distance between the right endpoint b and the tire bead baseline BL is H4, -5mm≤H8-H4≤5mm; H5-H4=h, and the radial distance between the vertex c and the right endpoint b is h.

3. The pneumatic tire of claim 2, wherein: The wire loop (23) is disposed in the area surrounded by the main part (31) and the reverse wrapping part (32), and the minimum distance between the outer side of the wire loop (23) and the right end point b is h4; The minimum distance between the outer surface of the wire loop (23) and the curve ab is h3, where h3 ≥ h4.

4. The pneumatic tire of claim 1, wherein: The radial outer side of the second triangular rubber (22) is close to the tire crown, and the distance between the upper end point of the axial outer side of the second triangular rubber (22) and the tire bead baseline BL is H1; The radial distance between the tire section width SW and the bead baseline BL is LSH, which satisfies: H1 / LSH=0.7~0.

9.

5. The pneumatic tire of claim 4, wherein: The radial distance between the outer axial end point f of the reverse wrapping part (32) and the bead baseline BL is H2, which satisfies: H2 / LSH=0.3~0.

5.

6. The pneumatic tire of claim 5, wherein: The curve ab intersects the main part (31) at the left end point a, the left end point a is the upper inner end point a of the first triangular rubber (21) in the axial direction, and the radial distance between the upper inner end point a and the bead baseline BL is H3, H3 / H2 = 1~1.

4.

7. The pneumatic tire of claim 1, wherein: It also includes a steel wire cord (4) disposed on the outer side of the tire body (3), wherein the distance between the outer axial end point e of the steel wire cord (4) and the outer axial end point f of the reverse wrapping part (32) is H6, where H6 = 10-16 mm.

8. The pneumatic tire of claim 7, wherein: The outer axial end point f of the reverse wrapping part (32) is projected onto the projection point p along a vertical line perpendicular to the main part (31). The distance between the projection point p and the inner axial end point g of the steel wire curtain (4) is H7, where H7 = -10 to 10 mm.

9. The pneumatic tire of claim 1, wherein: The elastic modulus of the first triangular rubber (21) is E1, where E1 = 12-15 MPa; The elastic modulus of the second triangular rubber (22) is E2, E2 = 3~6 MPa.

Images