Run-flat tire

Abstract

The run-flat tire comprises a tire tread, a tire side wall, a tire body and a tire bead, and the tire bead is not provided with a bead filler structure and is only composed of a steel wire ring which is gradually narrowed from bottom to top; the run-flat tire further comprises inner supporting rubber, the section of the inner supporting rubber is in a crescent shape, and the inner supporting rubber is located between the tire side lining and the tire body cord fabric. The section of the outer supporting rubber is triangular, and the outer supporting rubber is located between the tire body cord fabric and the tire side wall; the wear-resistant rubber is in contact with the rim; the sidewall rubber is covered on the carcass ply; wherein the outer support rubber, the wear-resistant rubber and the sidewall rubber adopt a pre-composite structural design. On the premise that apex does not exist, the modulus and size relation between all parts of the tire side wall is optimized, and the running time and distance of the tire in the air shortage state are prolonged; in addition, the design concept of pre-compounding the outer support rubber and the sidewall is adopted, so that the production complexity can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of automobile tires, and in particular to a run-flat tire. Background Art

[0002] A run-flat tire is a tire designed to be driven in a normal inflated state and can still travel a certain distance at a certain speed without any other accessories when deflated. With the development of the automobile industry, consumers have higher and higher requirements for automobile safety performance. Run-flat tires have the characteristic of maintaining a certain driving capacity and distance after the tire is punctured, which greatly improves the safety of vehicles in emergency situations, so the demand in the market is growing.

[0003] Although the existing run-flat tire design solves some problems, it still has the following shortcomings, such as:

[0004] U.S. Patent US6609550B2 discloses an inflatable tire, comprising a rubber bead apex extending radially outward from a bead core; a carcass composed of an inner carcass layer and an outer carcass layer, the inner carcass layer flipped around the bead core in each bead portion from the inside of the tire to the outside of the tire to form a pair of flipped portions and a main portion therebetween, the outer carcass layer extending to a position between the bead apex and the flanging portion; a wire rope reinforcement layer, comprising an axially inner portion and an axially outer portion, extending radially outward from the lower side of the bead core to the sidewall portion; the sidewall portion having an axially inner reinforcing rubber layer, the axially inner reinforcing rubber layer being arranged in the main portion of the inner carcass layer, and an axially outer reinforcing rubber layer, the axially outer reinforcing rubber layer being arranged between the outer carcass layer and the axially outer portion of the wire rope reinforcement layer. This solution adopts the design of internal and external support glue, which requires two support glue laminations in the production process, namely, one between the inner lining and the cord, and the other before the cord is turned over. The additional support glue lamination process will increase the single tire molding time; and the outer support glue is affixed to the upper arc surface of the inner support glue, and the lamination surface is uneven, which will affect the quality during the production process.

[0005] Chinese invention patent CN103826876 discloses a run-flat tire, comprising: a carcass, a belt layer, a pair of side reinforcement rubber layers, and a pair of bead apex rubber components. The bead apex rubber component includes a first bead apex rubber component arranged in the first bead portion and a second bead apex rubber component arranged in the second bead portion, the bead apex rubber components are each made of a rubber having high rigidity and are arranged between the main body portion and the folded portion of the carcass ply in each bead portion, so as to extend in a tapered shape from the bottom of the bead apex rubber component connected to the radial outer surface of the bead core to the radial outer end of the bead apex rubber component, wherein the first bead apex rubber component has a first apex height A1 greater than a second apex height A2 of the second bead apex rubber component, wherein each apex height is defined as a length from a center point of the bottom to a radial outer end in a tire cross section including the tire axis under standard conditions, in which the tire is fitted to a standard rim and inflated to a standard pressure but without a tire load, wherein the first side reinforcing rubber layer has a first inner end height B1 greater than a second inner end height B2 of the second side reinforcing rubber layer; and the tire has the same thickness at the same radial position on the corresponding first bead portion side and the second bead portion side. That is, a design is disclosed in which the inner and outer apex rubbers are not of equal height, and the inner and outer apex rubbers are of different heights, and the thickness is required to be the same at the same radial position of the tire. This places very high demands on the dimensional accuracy of the semi-finished product during the production process.

[0006] Chinese invention patent CN106671707 discloses a run-flat tire, which has: a carcass, which is composed of a carcass cord layer that is annularly spanned and extends between a pair of bead parts; a bead core, which is arranged on each bead part and is composed of an inner core and an outer core that clamp the end of the carcass cord layer from the inside and outside of the tire axial direction; and a side reinforcing rubber layer with a roughly crescent-shaped cross-section, which is arranged on the inner side of the carcass and the sidewall area, and on the outer surface of the bead part, a rim protection part protruding outward in the tire axial direction is formed at a position closer to the outside of the tire radial direction than the inner end of the side reinforcing rubber layer in the tire radial direction, and on the normal line erected from the top of the rim protection part to the carcass cord layer, the thickness of the side reinforcing rubber layer is 29% to 35% of the tire thickness. That is, a structure in which an apex rubber covers the bead, and the inner and outer apex rubbers clamp the end points of the carcass cord layer from the inside and outside of the tire axial direction. This requires specific equipment to produce this structure.

[0007] It can be seen that the design of existing run-flat tires, compared with ordinary tires, at least adds sidewall support rubber in the product structure. In addition, in order to improve the tire's ability to have sufficient support when it is deflated, the support rubber is usually widened and thickened, and the triangle rubber is heightened and enlarged to enhance the strength of the sidewall. The defects of such a design are: on the one hand, the design of widened and thickened support rubber increases the overall tire weight; on the other hand, the design of heightened and enlarged triangle rubber will affect the qualified rate of finished products in the product production process and reduce the comfort performance of the tire. Summary of the invention

[0008] The technical problem to be solved by the present invention is how to design a run-flat tire without apex rubber and inner and outer supporting rubber structures.

[0009] In order to solve the above technical problems, the present invention provides a run-flat tire, comprising a tread, a sidewall, a carcass and a bead, wherein the bead has no apex rubber structure and is only composed of a wire ring that gradually narrows from the bottom to the top; the run-flat tire also includes:

[0010] An inner support rubber, whose cross section is crescent-shaped, and the inner support rubber is located between the sidewall liner and the carcass cord;

[0011] An outer support rubber, the cross section of which is triangular, and the outer support rubber is located between the carcass cord and the sidewall;

[0012] A wear-resistant rubber, which contacts the rim; and

[0013] The sidewall rubber covers the carcass cord fabric; wherein the outer support rubber, the wear-resistant rubber and the sidewall rubber adopt a pre-composite structure design.

[0014] Furthermore, the wire rings are stacked and wound to form a structure that gradually expands from the center to the outside.

[0015] Furthermore, the thickness of the inner supporting glue and the outer supporting glue satisfies the relationship:

[0016] (T2+T3)=(1.10~1.20)×T1

[0017] (T4+T5)=(1.10~1.20)×T1

[0018] Among them, T1 represents the thickness of the inner support rubber at the 1 / 2SH position, T2 represents the thickness of the inner support rubber at the 1 / 3SH position, T3 represents the thickness of the inner support rubber at the 1 / 5SH position, T4 represents the thickness of the outer support rubber at the 1 / 3SH position, T5 represents the thickness of the outer support rubber at the 1 / 5SH position, and SH represents the tire section height.

[0019] Furthermore, let the elastic modulus of the inner supporting rubber be M1, and the elastic modulus of the outer supporting rubber be M2, then the relationship is satisfied: M1=M2.

[0020] Furthermore, the inner supporting glue and the outer supporting glue have the same formula.

[0021] Furthermore, the wear-resistant rubber is located between the outer supporting rubber and the sidewall rubber.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention optimizes the modulus and dimensional relationship between the various components of the sidewall without the use of apex rubber, thereby increasing the driving time and distance of the tire in a deflated state; at the same time, it improves the comfort of the product and reduces the weight and rolling resistance of the product; in addition, the design concept of pre-compounding the outer support rubber and the sidewall can reduce the complexity of production and improve the product qualification rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a partial cross-sectional view of a tire disclosed in an embodiment of the present invention, showing the structure of the inner and outer support rubbers;

[0025] Figure 2 A partial cross-sectional view of a tire disclosed in an embodiment of the present invention, showing the thickness of the inner and outer support rubbers at different positions;

[0026] Figure 3 This is a design diagram of the pre-composite structure of the outer support rubber, the wear-resistant rubber and the sidewall rubber disclosed in an embodiment of the present invention.

[0027] In the figure:

[0028] 10. Inner support rubber; 20. Outer support rubber; 30. Wear-resistant rubber; 40. Sidewall rubber. DETAILED DESCRIPTION

[0029] In order to make the technical scheme and technical effect of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0030] The present invention aims to provide a run-flat tire, which adopts an inner and outer support rubber, a triangle rubber-free structural design, and a design concept of pre-compounding the outer support rubber with the sidewall. At the same time, the modulus and size relationship between the various components of the sidewall are optimized to increase the time and distance the tire travels in a deflated state, and can reduce production complexity and improve product qualification rate.

[0031] refer to Figure 1The run-flat tire mainly includes tread, sidewall, carcass and bead. The bead has no apex structure and is only composed of wire rings that gradually narrow from the bottom to the top. The wire rings are stacked and wound to form a structure that gradually expands from the center to the outside. The purpose of this design is that the apex is greatly deformed during molding due to the influence of the cord wrapping and molding pressure. Therefore, the design without apex can reduce the uniformity problem caused by the deformation of the apex during molding, thereby improving the uniformity pass rate; in addition, the structure without apex reduces the radial stiffness of the tire sidewall, improves the comfort performance of the tire, and at the same time reduces the weight of the tire and saves costs.

[0032] Furthermore, the run-flat tire further comprises an inner support rubber 10, an outer support rubber 20, a wear-resistant rubber 30 and a sidewall rubber 40 which are sequentially arranged from the inside to the outside along the tire rubber radial direction. Specifically:

[0033] The cross section of the inner support rubber 10 is crescent-shaped, and the inner support rubber 10 is located between the sidewall inner liner and the carcass cord.

[0034] The cross section of the outer support rubber 20 is roughly triangular, and the outer support rubber 20 is located between the carcass cord and the sidewall.

[0035] The wear-resistant rubber 30 contacts the rim and is located between the outer supporting rubber 20 and the sidewall rubber 40 .

[0036] The sidewall rubber 40 covers the carcass cord to protect the carcass cord.

[0037] refer to Figure 3 The outer support rubber 20, the wear-resistant rubber 30 and the sidewall rubber 40 adopt a pre-composite structure design. The purpose of this design is to reduce the laminating process in the molding process, improve production efficiency, and thus improve the qualified rate of the product.

[0038] refer to Figure 2 , the thickness of the inner supporting glue 10 and the outer supporting glue 20 satisfy the relationship:

[0039] (T2+T3)=(1.10~1.20)×T1

[0040] (T4+T5)=(1.10~1.20)×T1

[0041] Among them, T1 represents the thickness of the inner support rubber 10 at the 1 / 2SH position, T2 represents the thickness of the inner support rubber 10 at the 1 / 3SH position, T3 represents the thickness of the inner support rubber 10 at the 1 / 5SH position, T4 represents the thickness of the outer support rubber 20 at the 1 / 3SH position, T5 represents the thickness of the outer support rubber 20 at the 1 / 5SH position, and SH represents the tire section height.

[0042] Furthermore, the formula of the inner support rubber 10 is the same as that of the outer support rubber 20. Let the elastic modulus of the inner support rubber 10 be M1, and the elastic modulus of the outer support rubber 20 be M2, then the relationship is satisfied: M1=M2. The purpose of this design is that when the tire is under zero air pressure, the load on the tire is mainly supported by the sidewalls, that is, the inner and outer support rubbers are the main load-bearing components. The inner and outer support rubbers with the same formula reduce the stress concentration caused by the difference in modulus, which is more conducive to the dispersion and transmission of stress. Combined with the design of the wire ring from bottom to top and from wide to narrow, it is conducive to the soft and hard transition from the tread to the rim, reducing stress concentration, thereby improving the durability of the tire.

[0043] The design parameters of this embodiment are experimentally verified as follows:

[0044] 1. Without considering the limitations of carcass material and the thickness and width of the inner and outer support rubbers, the performance of the tires made after the inner and outer support rubbers are limited is tested. The following table 1 lists the cases:

[0045] Table 1

[0046] External support glue Triangle M1 / M2 Comparative Example 1 none have / Example have none 1.00 Comparative Example 2 have none 1.20 Comparative Example 3 have none 0.85

[0047] The tires corresponding to the embodiment and comparative examples 1-3 in Table 1 were measured, and the measurement results are shown in Table 2:

[0048] Table 2

[0049]

[0050]

[0051] From Table 1 and Table 2 above, we can see that:

[0052] (1) This embodiment adds an outer support rubber and cancels the conventional apex rubber, while reducing the width and thickness of the inner support rubber. The outer support rubber and the sidewall adopt a pre-composite structure design and are produced together when the sidewall is pressed out. This does not increase the complexity and reduces the problem of low uniformity qualification rate caused by the wide inner support rubber. At the same time, the apex rubber is greatly deformed by the cord wrapping and molding pressure during molding. The design without apex rubber can reduce the poor uniformity problem caused by the deformation of the apex rubber during molding, thereby improving the uniformity qualification rate.

[0053] (2) Under zero air pressure conditions, the load on the tire is mainly supported by the sidewalls, that is, the inner and outer support rubbers are the main load-bearing components. The inner and outer support rubbers of the same formula are more conducive to the dispersion and transmission of stress. Combined with the wire ring, the design from bottom to top and from wide to narrow is conducive to the soft and hard transition from the tread to the rim, reducing stress concentration, thereby improving the durability of the tire.

[0054] (3) The structure without apex rubber reduces the radial stiffness of the tire sidewall and improves the comfort performance of the tire; at the same time, it can also reduce the weight of the tire and save costs.

[0055] 2. Based on the above experimental verification results, the performance of the tires made after the apex rubber and the inner and outer support rubbers are limited is tested, as shown in Table 3 below:

[0056] Table 3

[0057]

[0058]

[0059] The tires corresponding to Examples 1-2 and Comparative Examples 1-3 in Table 3 were measured, and the measurement results are shown in Table 4:

[0060] Table 4

[0061] stress Zero pressure durability performance Comfort index weight Comparative Example 1 3.65 72 100％ 100％ Example 1 3.04 156 105％ 90％ Example 2 3.09 79 101％ 88％ Comparative Example 2 3.27 108 106％ 91％ Comparative Example 3 3.30 111 103％ 91％

[0062] From Table 3 and Table 4 above, we can see that:

[0063] (1) Under zero air pressure conditions, the load on the tire is mainly supported by the sidewalls, that is, the inner and outer support rubbers are the main load-bearing components. According to the design of the present invention, the inner and outer support rubbers are of the same formula, which reduces the stress concentration caused by the difference in modulus.

[0064] (2) In the above-mentioned embodiment 1, the design concept of "equal thickness design of supporting materials" is adopted in the sidewall part to more evenly disperse the stress under zero air pressure conditions. In the above-mentioned comparative examples 2 and 3, the stress generated at the position with the smallest supporting material thickness is the greatest, and the failure position after the test is also the position with the greatest stress.

[0065] (3) When the tire is under zero pressure, the amount of sinking increases and a large amount of heat is generated during driving. The temperature of the tire sidewall running under zero pressure is measured using an infrared thermometer, and the maximum measured temperature reaches 150° C. to 170° C. In the above Example 2, the tire body material is PET, and its zero pressure durability performance is significantly reduced compared to RAYON with better thermal stability.

[0066] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A run-flat tire, comprising a tread, a sidewall, a carcass and a bead, characterized in that: The tire bead has no apex rubber structure and is only composed of a wire ring that gradually narrows from the bottom to the top; the run-flat tire also includes: An inner support rubber (10) having a crescent-shaped cross section, the inner support rubber (10) being located between the sidewall inner liner and the carcass cord fabric; An outer support rubber (20) having a triangular cross-section, the outer support rubber (20) being located between the carcass cord and the sidewall; A wear-resistant rubber (30) in contact with the rim; and A sidewall rubber (40) covering the carcass cord fabric; wherein the outer support rubber (20), the wear-resistant rubber (30) and the sidewall rubber (40) adopt a pre-composite structure design.

2. The run-flat tire according to claim 1, characterized in that: The wire rings are stacked and wound to form a structure that gradually expands from the center to the outside.

3. The run-flat tire according to claim 1, characterized in that: The thickness of the inner supporting glue (10) and the outer supporting glue (20) satisfy the relationship: (T2+T3)=(1.10~1.20)×T1 (T4+T5)=(1.10~1.20)×T1 Wherein, T1 represents the thickness of the inner supporting rubber (10) at the 1 / 2SH position, T2 represents the thickness of the inner supporting rubber (10) at the 1 / 3SH position, T3 represents the thickness of the inner supporting rubber (10) at the 1 / 5SH position, T4 represents the thickness of the outer supporting rubber (20) at the 1 / 3SH position, T5 represents the thickness of the outer supporting rubber (20) at the 1 / 5SH position, and SH represents the tire section height.

4. The run-flat tire according to claim 1, characterized in that: The elastic modulus of the inner supporting rubber (10) is denoted as M1, and the elastic modulus of the outer supporting rubber (20) is denoted as M2, and then the relationship is satisfied: M1=M2.

5. The run-flat tire according to claim 1, characterized in that: The inner supporting glue (10) and the outer supporting glue (20) have the same formula.

6. The run-flat tire according to claim 1, characterized in that: The wear-resistant rubber (30) is located between the outer supporting rubber (20) and the sidewall rubber (40).

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