Highly durable gradient reinforced composite for aircraft tires and aircraft tire bead structure

Abstract

A high-durability gradient-reinforced composite material for an aircraft tire and a bead structure of an aircraft tire, the high-durability gradient-reinforced composite material having a Shore A hardness of 50°-75°, a 100%-300% modulus of ≥5 MPa, a tensile strength of ≥20 MPa, and an elongation at break of ≥450%; the high-durability gradient-reinforced composite material having a hardness gradient and / or a modulus gradient in the thickness direction. The bead structure of the aircraft tire is provided with a bead reinforcing rubber between the bead rubber and the rim edge, the bead reinforcing rubber being made of the aforementioned high-durability gradient-reinforced composite material, the hardness and / or the modulus of the bead reinforcing rubber gradually increasing from the bead rubber to the rim edge, effectively reducing the concentration of dynamic strain, reducing the heat generation, avoiding material aging and performance degradation caused by high temperature, significantly improving the durability and fatigue resistance of the bead structure, and meeting the use requirements of the aircraft tire under high load and high frequency strain working conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aviation tires, in particular to a high-durability gradient-reinforced composite material for aviation tires, a bead structure of an aviation tire, and a forming method and application thereof. BACKGROUND

[0002] Aviation tires are the only contact components between the aircraft and the ground, and bear most of the load and impact during the take-off and landing of the aircraft. During use, the tire is subjected to high-frequency rolling under heavy load and high speed, and the periodic strain rate of the rubber material at the bead position is significantly increased. In particular, the strain of the bead rubber of the radial aviation tire under high load and high-speed rolling conditions is significantly higher than that of the shoulder part. Due to the viscoelastic properties of rubber, the strain lags behind the stress, resulting in the conversion of hysteresis energy loss into heat, so the heat generation of the bead rubber of the radial aviation tire is much greater than that of other parts, and the high temperature causes the performance of the bead rubber and the cord to rapidly decrease and result in failure problems.

[0003] In addition, under the working conditions of the tire, the rubber layer close to the rim is subjected to a large compressive stress, and the direction of action is from the rim to the center of the tire, while the rubber and cord of the carcass directly wrapped by the cord layer in the bead are subjected to tensile stress, and the direction is the arrangement direction of the cord, i.e. from the bead to the sidewall, so the stress difference between the bead rubber and the rubber directly wrapped by the cord layer of the carcass is large, and a large shear stress is generated between the bead rubber layer and the carcass directly wrapped by the cord layer, which easily leads to delamination, cracking and other failure phenomena of the bead rubber, seriously affecting the durability of the bead.

[0004] In order to improve the durability of the bead of the radial aviation tire and provide safety protection for the aircraft, a reasonable bead structure design is urgently needed, which can not only reduce the shear stress between the rubber and the cord layer, but also effectively control the strain of the bead rubber, thereby significantly prolonging the service life of the tire and reducing the maintenance cost.

[0005] The invention JPH09155884A discloses a tire forming method and a tire by controlling the temperature gradient of an unvulcanized tire through a vulcanizing machine mold. The technology forms a modulus gradient in the thickness direction of the tread rubber by different heating temperatures inside and outside. The modulus gradient gradually increases along the thickness direction from the tread surface of the tread rubber, and the modulus gradient corresponds to a change rate in the range of 2% to 5% per 1 mm of the thickness of the tread rubber. However, this invention mainly designs the tread rubber of the vehicle tire, the overall modulus of the tread rubber is high, and the reference and effect of the shear stress distribution and strain control at the bead position are low and limited, and the invention obtains the modulus gradient through the temperature gradient in the tire forming, which has low accuracy and controllability, and is difficult to solve the problem of easy failure of the bead position of the aviation tire under high frequency and high pressure conditions.

[0006] For the design of the bead durability, the invention CN103010460B discloses a radial aviation tire capable of reducing interface stress, strain and heat generation and improving the bead durability, which comprises a tread rubber, a belt layer, a carcass ply and a pair of steel wire beads. At the bead position, two layers of stress buffer rubbers with different stiffness and thickness are arranged between the outer side of the carcass ply and the sidewall rubber, and the carcass ply is arranged between the two layers of stress buffer rubbers. The two layers of stress buffer rubbers with different stiffness and thickness are as follows: the Shore hardness of the first layer of low-hardness rubber is 63-68 degrees, and the thickness is 2-5 mm; the Shore hardness of the second layer of stress buffer rubber is 60-65 degrees, and the thickness is 4-7 mm. The Shore hardness of the second layer of stress buffer rubber is 2-5 degrees less than that of the first layer of stress buffer rubber. The radial aviation tire of the invention improves the bead durability by more than 80% through the above structural design, and the dynamic performance can meet the requirements of the airworthiness standard (GJB683A). However, the thickness is an empirical value, and cannot be calculated according to the tire level of different sizes, which has poor applicability.

[0007] The invention CN103009932B discloses a radial aviation tire capable of reducing interface stress and improving the bead durability. At the bead position, a transition rubber is arranged on the outer side of the carcass ply, with a thickness of 2-4 mm and a Shore hardness of 60-70 degrees. Two layers of buffer fiber ply layers are arranged outside the transition rubber, with a cord density of 35-90 roots / 100 mm, a cord and circumferential angle of 20°-90°, and the warp of the two layers of plies being crosswise arranged relative to the radial direction. The improved radial aviation tire can reduce the interface stress, strain and heat generation between the carcass and the outer rubber at the bead position, and the bead durability is improved by more than 80% under harsh conditions. The dynamic performance can meet the requirements of the airworthiness standard (GJB683A). However, the hardness of the two layers of buffer rubbers gradually decreases from inside to outside, which is not conducive to the wear resistance of the bead, and the hardness and modulus of the sidewall rubber are not clear, and the modulus gradient is not clear.

[0008] The improvement of the bead durability will provide a strong guarantee for the safety performance of the aircraft, and will greatly reduce the maintenance and use cost of the aircraft. Therefore, how to reduce the shear stress between the bead rubber and the bead positive ply layer and the strain of the bead rubber through reasonable structural design and rubber modulus ratio is the key link to improve the bead durability of the radial aviation tire, and is a problem to be solved by the skilled in the art. SUMMARY

[0009] In view of the defects in the prior art, the application provides a high-durability gradient-reinforced composite material for an aviation tire, a bead structure of an aviation tire, and a forming method and application thereof. The hardness and modulus of the high-durability gradient-reinforced composite material are designed to gradually increase from the inside to the outside in the thickness direction, the outer layer has high hardness and modulus to enhance the wear resistance, and the inner layer has low hardness and modulus to reduce the shear stress between the bead rubber material and the carcass ply, thereby comprehensively improving the durability of the bead of the aviation tire.

[0010] In a first aspect, the application provides a high-durability gradient-reinforced composite material for an aviation tire, wherein the Shore A hardness of the high-durability gradient-reinforced composite material is 50°-75°, the 100%-300% modulus is greater than or equal to 5 MPa, the tensile strength is greater than or equal to 20 MPa, and the elongation at break is greater than or equal to 450%.

[0011] In the thickness direction, the high-durability gradient-reinforced composite material has a hardness gradient and / or a modulus gradient.

[0012] Preferably, the hardness of the high-durability gradient-reinforced composite material gradually increases and the modulus gradually increases from the inside to the outside in the thickness direction.

[0013] The impact load on the aviation tire is much larger than that on the automobile tire, the sinking rate is 20%-80%, and the sinking rate of the automobile tire is about 10%-20%. Therefore, the mechanical property indexes of the aviation tire are generally higher than those of the automobile tire, including hardness, modulus, tensile strength, elongation at break, etc. The Shore A hardness of the composite material of the application is 50°-75°, the 100%-300% modulus is greater than or equal to 5 MPa, the tensile strength is greater than or equal to 20 MPa, and the elongation at break is greater than or equal to 450%. Further, the hardness gradient and modulus gradient suitable for the aviation tire are introduced in the thickness direction. When the composite material is used in the bead structure of the aviation tire, the bead structure has both flexibility and wear resistance, and the stress distribution and material durability are optimized, thereby meeting the high-performance requirements of the aviation tire under complex use environment.

[0014] Preferably, the hardness gradient and / or modulus gradient of the high-durability gradient-reinforced composite material is formed by at least one of the following ways:

[0015] 1) The high-durability gradient-reinforced composite material comprises a reinforcing agent, and the content of the reinforcing agent is gradient-distributed in the thickness direction.

[0016] 2) In the thickness direction, the high-durability gradient-reinforced composite material forms a vulcanization degree gradient.

[0017] Reinforcing agents for aircraft tires include at least one of carbon black, silica, graphene, and carbon nanotubes. These reinforcing agents significantly improve the physical and mechanical properties of tire rubber, such as strength, abrasion resistance, wet skid resistance, and tear resistance, while reducing rolling resistance and economic costs, all while lowering the cost of the rubber. The content of the reinforcing agent has a significant effect on the hardness and modulus of the rubber; therefore, by distributing reinforcing agents in different content gradients within the rubber matrix, the desired performance gradient can be obtained quickly and easily. On the other hand, the properties of rubber are closely related to the vulcanization process. With the same material composition, changing the vulcanization temperature and / or vulcanization time can adjust the degree of vulcanization of the rubber compound, and the desired performance gradient can also be achieved through gradient differences in the degree of vulcanization.

[0018] Therefore, this invention, through the design and / or control of the gradient distribution of reinforcing agent content and the gradient of vulcanization degree, can effectively form a performance gradient in the composite material, thereby meeting further design requirements. Specific reinforcing agent content and vulcanization process conditions can be designed and controlled based on the rubber compound ratio and performance requirements.

[0019] Preferably, the high-durability gradient-reinforced composite material comprises n reinforcing layers stacked sequentially, where n is an integer greater than 1, and the composite material satisfies at least one of the following conditions:

[0020] 1) The reinforcing agent content of the innermost first reinforcing layer is C1, and the reinforcing agent content of the nth reinforcing layer is C. n C n Independent satisfaction: C1×p n-1 The content coefficient p is 1.1-2;

[0021] 2) The Shore A hardness of the innermost first reinforcing layer is A1, and the Shore A hardness of the nth reinforcing layer is A. n A n Independent satisfaction: A1×j n-1 The hardness coefficient j is 1.01-1.5;

[0022] 3) The constant tensile stress of the first reinforcing layer located on the innermost side is E1, and the constant tensile stress of the nth reinforcing layer is E1. n E n Independently satisfying E1×k n-1 The modulus coefficient k is 1.05-2.

[0023] The composite material itself can be a one-piece structure, and the performance gradient in the one-piece structure is obtained by the aforementioned adjustment mode, but more preferably, a layered material with a performance gradient is adopted, and a one-piece structure is formed through a vulcanization process. By adopting the layered stacking mode, on the one hand, it is beneficial to precisely control the performance increment or decrement value of each layer, and the influence of the mixing process link is slightly smaller, on the other hand, the specific rubber compound ratio of each layer can also be adjusted as needed, for example, the same base rubber is used with different reinforcing agents or other types of additives, or the types and amounts of each component such as base rubber are adjusted, so as to achieve the required comprehensive performance. In addition, the layered stacking is also more convenient for dividing the vulcanization process adjustment area, and when the performance gradient is obtained on the basis of forming a vulcanization degree gradient, it is more accurate.

[0024] The value of the hardness coefficient j is set to be between 1.01 and 1.5, which ensures that the hardness of each outer layer of the composite material is higher than that of the inner layer from the inside to the outside, which helps to optimize the stress distribution. The higher the hardness, the stronger the rigidity of the rubber compound, which helps to enhance the support force of the outer layer of the bead, reduces the excessive deformation of the rim part due to repeated stress, and avoids early wear and aging of the contact surface between the rim and the bead rubber layer. Similarly, the modulus determines the tensile performance of the material, the higher the modulus, the more rigid the material, the more it can withstand large deformation without permanent deformation. The modulus coefficient k is set to be 1.05-2, and the modulus of the reinforcing rubber of each outer layer is higher than that of the inner layer from the inside to the outside. The increase in modulus enables the bead to have a proper balance of rigidity and flexibility at different positions. The high modulus of the outer layer can withstand greater stress, while the lower modulus of the inner layer helps to alleviate the transmission of external stress and avoid local damage due to excessive rigidity. Furthermore, the application preferably designs the content coefficient p, which increases the content of the reinforcing agent in each outer layer of the composite material from the inside to the outside, and the content gradient of the reinforcing agent has a good corresponding relationship and designability with the hardness gradient and modulus gradient corresponding thereto through the overall vulcanization process.

[0025] In a second aspect, the application provides a high-durability aviation tire bead structure, which comprises a steel wire ring, a bead filler, a sidewall rubber, a bead reinforcing rubber, and a bead rubber.

[0026] The bead reinforcing rubber is made of the aforementioned high-durability gradient-reinforced composite material, and the hardness of the bead reinforcing rubber gradually increases from the bead rubber to the rim edge, and / or the modulus gradually increases.

[0027] Preferably, the bead reinforcing rubber mainly comprises base rubber, reinforcing agent (or reinforcing agent), and one or more of silane coupling agent, protective wax, antioxidant, uniformizing agent, accelerator, vulcanizing agent, and anti-scorching agent.

[0028] The raw materials of the bead reinforcing rubber include, by weight:

[0029] 100 parts of base rubber

[0030] 20-100 parts of reinforcing agent

[0031] 5-50 parts of auxiliary agent

[0032] In the base rubber, natural rubber accounts for 70-100 wt%, and other optional components include synthetic rubbers such as butadiene rubber and styrene-butadiene rubber. For example, in a base rubber composition of 100 parts, 90 parts are natural rubber and 10 parts are styrene-butadiene rubber. To meet the high-performance requirements of aerospace tire compounds, the base rubber is mainly high-performance natural rubber, with a natural rubber proportion of 70-100 wt% per 100 parts of base rubber, preferably 80-100 wt%. The proportion of natural rubber in aerospace tire compounds is much higher than that in automotive tire compounds. In addition, a small amount of reclaimed rubber can be used in the base rubber, with a reclaimed rubber content of less than 5 wt%, preferably less than 3 wt%.

[0033] The reinforcing agent includes at least one of carbon black (e.g., N330 carbon black, N339 carbon black, N220 carbon black), silica, graphene, and carbon nanotubes. The reinforcing agent (or strengthening agent) is beneficial for improving the hardness, abrasion resistance, and tensile strength of the rubber compound. In this invention, based on the use of reinforcing agents, the content of the reinforcing agent is preferably designed in a gradient manner to create a performance gradient.

[0034] Additives include, but are not limited to, silane coupling agents, protective waxes, antioxidants, homogenizers, accelerators, vulcanizing agents, and anti-scorching agents.

[0035] The silane coupling agent includes at least one of Si-69, KH-550, KH-560, KH-570, KH-845-4, TESPT and TESPD, and its amount is about 0.1-10% of the reinforcing agent amount;

[0036] The protective wax includes at least one of paraffin oil, protective wax RP-3, and protective wax RW-101, with an amount of approximately 1-10 parts;

[0037] The antioxidants mainly include amine antioxidants and phenolic antioxidants. Amine antioxidants include ketone amines, aldehyde amines, diaryl secondary amines, diphenylamines, p-phenylenediamines, and alkylaryl secondary amines, while phenolic antioxidants include substituted monohydric phenols, polyhydric phenols, sulfurized disubstituted phenols, and alkyl disubstituted phenols. Specifically, antioxidants for aircraft tires may include at least one of antioxidants 4020, 4010NA, RD, and IPPD, with a total dosage of approximately 0.2-2% of the base rubber weight.

[0038] The homogenizing agent includes at least one of homogenizing agent A78, homogenizing agent 145A, and homogenizing agent UB4000, and is used in an amount of 1-5 parts.

[0039] The types of accelerators mainly include thioamino compounds, guanidine compounds, thiazole compounds, sulfenamide compounds, and thiuram compounds, specifically including at least one of accelerators DZ, NOBS, and TMTD, with a dosage of 1-5 parts.

[0040] The vulcanizing agent includes at least one of sulfur, DCP, and zinc oxide, and is used in an amount of 1-10 parts;

[0041] The scorching inhibitor mainly includes nitroso compounds, sulfenamides, N-cyclohexylthiophthalimide, N,N'-m-phenylenebismaleimide, etc., specifically including at least one of CTP, HTM, NA and salicylic acid, with a dosage of 0.1-3 parts.

[0042] In the current field of radial tire technology, the hardness and modulus of bead reinforcement are basically uniform, resulting in a single function and a lack of non-uniform performance design. Because different parts of the bead experience different loads and stress states, a uniform hardness structure exacerbates stress concentration, especially between the rubber and the carcass ply and near the rim. Furthermore, the bead undergoes repeated deformation during high-speed rolling, and a uniform modulus structure cannot adapt to the stress differences within the bead, leading to ineffective strain dispersion. Dynamic strain concentrates in localized areas, causing energy loss and conversion into heat, further exacerbating the heat generation problem of the rubber material. Moreover, the viscoelasticity of the rubber material causes strain to lag behind stress; a uniform modulus design cannot create a smooth strain transition in different stress areas, resulting in greater internal friction and hysteresis losses. Accumulated heat accelerates rubber aging and performance degradation.

[0043] This invention optimizes tire stress distribution by incorporating a hardness and modulus gradient in the bead reinforcement between the bead rubber and the rim edge. Specifically, the hardness and modulus gradient design allows the high hardness and high modulus of the outer reinforcement layer to adapt to the high-pressure stress near the rim edge, while the lower hardness and modulus of the inner reinforcement layer allow it to buffer stress when approaching the tire carcass ply. Through this hardness and modulus gradient design, the bead reinforcement exhibits significant advantages in stress distribution, heat generation reduction, and improved fatigue resistance, resulting in more durable and reliable tires under high-frequency and high-load conditions, meeting the stringent requirements of aviation tires.

[0044] Preferably, from the bead rubber towards the rim edge, the high-durability gradient reinforced composite material sequentially comprises a first reinforcing layer, a second reinforcing layer, and a third reinforcing layer, satisfying at least one of the following conditions:

[0045] 1) The Shore A hardness A1 of the first reinforcing layer is 55°-60°, and the tensile stress at 100%-300% is 5-10 MPa;

[0046] 2) The Shore A hardness A2 of the second reinforcing layer is 60°-65°, and the tensile stress at 100%-300% is 8-14 MPa;

[0047] 3) The Shore A hardness A3 of the third reinforcing layer is 65°-70°, and the constant tensile stress is ≥12MPa at 100%-300%.

[0048] Given that the layered lamination method allows for more precise design and control of hardness and modulus gradients, as well as the size limitations of the bead reinforcement, when applied to high-durability aircraft tires, the composite material of this invention preferably has three reinforcing layers from the bead to the rim edge, with the hardness and modulus of the three reinforcing layers gradually increasing.

[0049] Specifically, each reinforcing layer meets the following requirements: Shore A hardness of 50°-75°, tensile stress ≥5MPa at 100%-300% elongation, tensile strength ≥20MPa, and elongation at break ≥450%. In addition to forming a gradient distribution of hardness and modulus among the reinforcing layers, the tensile strength and elongation at break also show an increasing trend from the first reinforcing layer to the third reinforcing layer.

[0050] Preferably, the bead structure satisfies at least one of the following conditions:

[0051] 1) The ratio of the width W1 of the first reinforcing layer to the radius R of the rim edge is 1-1.2;

[0052] 2) The ratio of the width W2 of the second reinforcing layer to the width W1 of the first reinforcing layer is 1.5-2;

[0053] 3) The ratio of the width W3 of the third reinforcing layer to the width W2 of the second reinforcing layer is 1.5-2;

[0054] 4) The ratio of the total thickness B1 of the bead reinforcement and sidewall rubber to the total thickness B2 of the top skeleton material of the triangular rubber meets the following requirements:

[0055] When calculating the total thickness B1 of the bead reinforcement and sidewall rubber, the thickness refers to the size of the rubber sheet on a cross-section passing through the tire axis, from the bead rubber towards the rim edge. The "tire axis" refers to the tire's rotation axis. When the reinforcing layer is a uniform sheet, the thickness is a single value. When the reinforcing layer has an arc shape or other irregular structure, the thickness is calculated based on the maximum value. For example, if the first reinforcing layer is an arc-shaped strip, its thickness is the distance from the highest point of the arc side to the other side. The width is the maximum size of the sheet in the direction perpendicular to the thickness direction on the cross-section. Based on the bead stress and the bonding and reinforcing effect of the bead reinforcement, preferably, the thickness of the first reinforcing layer ≥ the thickness of the second reinforcing layer ≥ the thickness of the third reinforcing layer, and the width of the first reinforcing layer ≤ the width of the second reinforcing layer ≤ the width of the third reinforcing layer.

[0056] The total thickness B2 of the triangular rubber top skeleton material includes the total thickness of the carcass front ply, back ply, and bead reinforcement layer. The thickness ratio ensures that the contact area between the bead rubber and the rim edge has sufficient thickness, allowing the bead to effectively distribute the high-pressure stress from the rim edge during contact. If the bead thickness is insufficient, the support of the bead rubber at the rim edge is weak, making it prone to excessive deformation or wear due to uneven load distribution. Maintaining the ratio within the range of 0.75-1 ensures that the bead area has the necessary thickness to support the rim pressure without causing excessive stiffness or increased weight in the tire due to excessive thickness.

[0057] This invention conducts adaptive research on different bead sizes, including designing the width and thickness of the bead reinforcement adhesive based on the specific dimensions of materials such as the rim, sidewall rubber, and gusset rubber. Compared with existing technologies that prepare uniform-sized reinforcement adhesives for single tire application, this invention offers better targeting and actual reinforcement effects. Especially in the harsh operating environment where the impact load on aircraft tires is much greater than that on automobile tires, in addition to designing the hardness and modulus of the bead reinforcement adhesive, it also configures specific bead reinforcement adhesives according to the specific size of the aircraft tire, which has significant implications for performance improvement, durability, and safety assurance.

[0058] Preferably, the bead structure satisfies at least one of the following conditions:

[0059] 1) The Shore A hardness of the sidewall rubber is 68°-74°, and the tensile stress at 100%-300% is ≥15MPa;

[0060] 2) The Shore A hardness of the triangular rubber is 88°-94°;

[0061] 3) The ratio of the height H of the triangular rubber to the diameter D of the steel wire ring satisfies:

[0062] 4) The ratio of the height difference H2 between the top of the triangular rubber and the rim to the rim height H1 is 1:(4-9).

[0063] The sidewall rubber is made of wear-resistant rubber, and the base rubber of the wear-resistant rubber includes one or more of natural rubber, butyl rubber, fluororubber, hydrogenated nitrile rubber and polyurethane rubber. Its hardness and modulus can be adjusted by filling with a high content of reinforcing agent.

[0064] The triangular bead uses a high-modulus rubber compound, including one or more of high-hardness nitrile rubber, high-hardness hydrogenated nitrile rubber, polyurethane compound, and silicone rubber. The triangular bead compound contains a high content of reinforcing agents such as carbon black to achieve a high modulus. After mixing, the compound is extruded and installed on the bead ring, then covered with a cord fabric or rubber-coated cord fabric to form a single unit. The height of the triangular bead is close to or slightly larger than the diameter of the bead ring, allowing it to form a good support structure around the bead ring, optimizing the stress distribution of the bead under high loads and avoiding localized deformation of the bead rubber due to insufficient height. A suitable height ratio ensures that the triangular bead is neither too high (leading to excessive rigidity) nor too low (resulting in insufficient support), thus achieving a balanced and stable bead structure under load.

[0065] By controlling the ratio of the height difference between the top of the tread bead and the rim flange, the contact condition between them can be controlled. This allows the load on the rim to be distributed layer by layer across different parts of the tire bead, preventing stress concentration on a single contact surface. A suitable height difference ratio ensures that the top of the tread bead effectively contacts the rim flange without protruding excessively. This reduces wear or peeling caused by localized stress concentration during tire rolling, improving the tire's wear resistance and stability.

[0066] More preferably, the bead reinforcement extends from the lower tire sidewall to the bottom of the bead ring; the density of the skeleton cords of the bead reinforcement is less than the density of the carcass cords.

[0067] The bead reinforcement rubber has a lower cord density than the carcass ply, creating a modulus transition zone between the bead and carcass layers. This reduced cord density allows for a flexible transition in ply density, thereby minimizing the modulus difference between the bead and carcass layers and reducing shear stress between the rubber and ply layers.

[0068] The density transition design of the bead reinforcement, along with its hardness and modulus gradient, works synergistically to ensure smoother stress transfer within the bead structure and reduce shear stress concentration between bead layers. This synergistic effect ensures the dynamic stability of the bead under high-frequency, high-load conditions, enabling the tire to maintain a longer service life under complex operating conditions. It also enhances the structure's fatigue resistance, significantly improving the safety and reliability of aviation tires under extreme conditions.

[0069] Thirdly, the present invention also provides a method for preparing the high-durability aircraft tire bead structure, comprising the following steps:

[0070] Step 1: Wrap the steel wire rings and triangular rubbers through the carcass ply;

[0071] Step 2: Apply the bead reinforcement layer to the outside of the tire carcass ply, starting from the bottom of the steel wire bead and moving upwards;

[0072] Step 3: Adhere the high-durability gradient reinforced composite material to the side of the bead reinforcement layer facing the rim edge to form a bead reinforcement adhesive;

[0073] Step 4: Apply sidewall adhesive to the outside of the high-durability gradient reinforced composite material;

[0074] Step 5: Starting from the bottom of the high-durability gradient reinforced composite material, cover the bead reinforcement layer and / or the carcass ply with bead adhesive.

[0075] Preferably, the carcass ply includes reverse-wrapped ply and forward-wrapped ply, and step one, which involves wrapping the steel wire ring and triangular rubber into an integral structure, specifically includes:

[0076] 1) Lay the reverse-wrapped fabric layer by layer on the aircraft tire forming equipment;

[0077] 2) Install steel wire rings and triangular rubber at the designated positions, and reverse the curtain fabric manually or using a reverse wrapping device;

[0078] 3) Wrap the front curtain over the back curtain.

[0079] Preferably, from the bead seal towards the rim edge, the high-durability gradient reinforced composite material sequentially includes a first reinforcing layer, a second reinforcing layer, and a third reinforcing layer. In step three, the high-durability gradient reinforced composite material specifically includes:

[0080] 1) Outside the bead reinforcement layer, the first reinforcement layer is attached upwards from the corresponding position at the top of the wire bead; the first reinforcement layer is preferably an arc-shaped strip film, with the thickness gradually decreasing from the middle to both ends of the film. The arc-shaped strip film can be symmetrical or asymmetrical in configuration, which can better fill the recessed area on the outside of the bead reinforcement layer.

[0081] 2) On the outside of the first reinforcing layer, start from the corresponding position in the middle of the wire ring and stick the second reinforcing layer upwards; on the basis of the first reinforcing layer, the second reinforcing layer can be a film of uniform thickness;

[0082] 3) Outside the second reinforcing layer, at or near the starting position of the second reinforcing layer, the third reinforcing layer is pasted upwards; the third reinforcing layer can be a film of uniform thickness.

[0083] Preferably, in step four, the sidewall adhesive is pasted from top to bottom relative to the third reinforcing layer, and more preferably from the shoulder of the tire downwards.

[0084] Preferably, in step five, the bead adhesive starts from the bottom of the third reinforcing layer and covers at least the bottom of the entire bead structure.

[0085] Fourthly, the present invention also provides the application of the high-durability gradient reinforced composite material, or the high-durability aircraft tire bead structure, or the high-durability aircraft tire bead structure obtained by the preparation method in military and / or civil aircraft tires.

[0086] The present invention has at least the following beneficial effects:

[0087] (1) The high-durability gradient-reinforced composite material for aircraft tires and the high-durability aircraft tire bead structure using the composite material provided by the present invention, by designing a hardness gradient and / or modulus gradient in the thickness direction of the composite material, enables the outer layer of the composite material to have higher hardness and modulus, effectively withstand high pressure stress, and reduce material wear and aging. At the same time, the inner layer has lower hardness and modulus, which can alleviate stress differences, reduce shear stress, and optimize stress distribution. This gradient design effectively reduces the concentration of dynamic strain, reduces heat generation, avoids material aging and performance degradation caused by high temperature, and significantly improves the durability and fatigue resistance of the composite material and its bead structure, meeting the usage requirements of aircraft tires under high load and high frequency strain conditions.

[0088] (2) By controlling the hardness, height, and other dimensions of the triangular rubber, this invention ensures that the triangular rubber has an appropriate support height in the tire bead, providing effective structural support while avoiding rigidity imbalance caused by excessive or insufficient height. At the same time, these ratios ensure proper contact between the top of the triangular rubber and the rim, distributing the load layer by layer, effectively avoiding stress concentration, reducing local wear or peeling, and improving the overall wear resistance and stability of the tire bead.

[0089] (3) Based on the dimensions and performance of components such as the rim, wire bead, triangular rubber and sidewall rubber of the aircraft tire, the present invention comprehensively designs a multi-layered gradient reinforced composite material and the dimensions and performance of each reinforcing layer. By adjusting the amount of reinforcing agent and / or the degree of vulcanization, the high-durability gradient reinforced composite material is simply and effectively molded to obtain a high-durability aircraft tire bead structure. The aforementioned design and molding methods have wide adaptability and adjustability and can be promoted and used in multiple models of military or civilian aircraft tires. Attached Figure Description

[0090] Figure 1 This is a cross-sectional view of the high-durability aircraft tire bead structure of the present invention;

[0091] Figure 2 This is a schematic diagram showing the dimensions of the high-durability aircraft tire bead structure of the present invention.

[0092] Explanation of reference numerals in the attached diagram: 1-Steel wire ring, 2-Triangle rubber, 3-Carcass ply, 4-Bead reinforcement layer, 5-First reinforcement layer, 6-Second reinforcement layer, 7-Third reinforcement layer, 8-Sidewall rubber, 9-Bead rubber, 10-Rim. Detailed Implementation

[0093] To better understand the above technical solutions, a detailed description of the solutions will be provided below in conjunction with the specification and specific implementation methods. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0094] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0095] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0096] The following will be combined with the appendix Figures 1-2 The content of this invention elaborates on the high-durability aircraft tire bead structure disclosed in this invention. The thickness of the high-durability gradient reinforced composite material (or bead reinforcement) of this invention refers to the size of the rubber sheet in the direction from the bead rubber towards the rim edge on a cross-section passing through the tire axis. The "tire axis" refers to the tire's rotation axis. The width of the high-durability gradient reinforced composite material (or bead reinforcement) refers to the maximum size of the rubber sheet in the direction perpendicular to the thickness direction on the cross-section passing through the tire axis.

[0097] like Figure 1 As shown, a high-durability aircraft tire bead structure made of a high-durability gradient reinforced composite material specifically includes: tire components such as a steel wire bead 1, a triangular rubber 2, a carcass ply 3, a bead reinforcement layer 4, a sidewall rubber 8, a bead reinforcing rubber, a bead rubber 9, and a rim 10, wherein:

[0098] (1) Bead reinforcement, formed of high-durability gradient reinforced composite material, is disposed between bead adhesive 9 and the edge of rim 10. From bead adhesive 9 to the edge of rim 10, bead reinforcement forms a gradually increasing hardness gradient and / or a gradually increasing modulus gradient, preferably both hardness and modulus gradually increase.

[0099] The high-durability gradient-reinforced composite material comprises n reinforcing layers stacked sequentially, where n is an integer greater than 1, preferably 3-5. Preferably, but not limited to, the hardness gradient and / or modulus gradient can be formed by at least one of the following methods:

[0100] 1) Gradient of reinforcing agent content:

[0101] The reinforcing agent content of the innermost first reinforcing layer 5 is C1, and the reinforcing agent content of the nth reinforcing layer is C. n C n Independent satisfaction: C1×p n-1 The content coefficient p is 1.1-2;

[0102] Optionally, when the composite material contains three reinforcing layers, the ratio of the reinforcing agent content of the first reinforcing layer 5 to the reinforcing agent content of the second reinforcing layer 6 to the reinforcing agent content of the third reinforcing layer 7 is (4-5):(5-6):(6-7);

[0103] The reinforcing agent includes at least one of carbon black, silica, graphene, and carbon nanotubes.

[0104] 2) Vulcanization time gradient:

[0105] The curing time of the innermost first reinforcing layer 5 is t1, and the curing time of the nth reinforcing layer is t. n , t n Independent satisfaction: t1×q n-1 The time coefficient q is 1.05-2;

[0106] Optionally, when the composite material contains three reinforcing layers, the ratio of the vulcanization time of the first reinforcing layer 5 to the vulcanization time of the second reinforcing layer 6 to the vulcanization time of the third reinforcing layer 7 is 1:(1.05-1.5):(1.3-1.8).

[0107] 3) Vulcanization temperature gradient: The vulcanization temperature of the innermost first reinforcing layer 5 is T1, and the vulcanization temperature of the nth reinforcing layer is T. n T n Independent satisfaction: T1×m n-1 The temperature coefficient m is 1.05-1.5;

[0108] Optionally, when the composite material contains three reinforcing layers, the ratio of the vulcanization temperature of the first reinforcing layer 5 to the vulcanization temperature of the second reinforcing layer 6 to the vulcanization temperature of the third reinforcing layer 7 is 1:(1.05-1.25):(1.2-1.5).

[0109] Performance gradients can be designed and controlled by one or a combination of conditions, such as the gradient of reinforcing agent content, the gradient of vulcanization temperature, and the gradient of vulcanization time. However, it is preferable to control only one or two conditions, otherwise the process cost will be high and the gradient accuracy will be difficult to control.

[0110] The bead reinforcement adhesive includes at least a first reinforcing layer 5, a second reinforcing layer 6, and a third reinforcing layer 7, with the following performance gradient design:

[0111] 1) Hardness gradient:

[0112] The Shore A hardness of the innermost first reinforcing layer 5 is A1, and the Shore A hardness of the nth reinforcing layer is A. n A n Independent satisfaction: A1×j n-1 The hardness coefficient j is 1.01-1.5;

[0113] Optionally, when the composite material contains three reinforcing layers, the Shore A hardness A1 of the first bead reinforcing layer is 55°-60°, the Shore A hardness A2 of the second bead reinforcing layer is 60°-65°, and the Shore A hardness A3 of the third bead reinforcing layer is 65°-70°, and A1 < A2 < A3.

[0114] 2) Modulus gradient:

[0115] The 100%-300% constant tensile stress of the innermost first reinforcing layer 5 is E1, and the 100%-300% constant tensile stress of the nth reinforcing layer is E. n E n Independently satisfying E1×k n-1 The modulus coefficient k is 1.05-2.

[0116] Optionally, the 300% tensile stress E1 of the first reinforcing layer 5 is 5-10 MPa, the 300% tensile stress E2 of the second reinforcing layer 6 is 8-14 MPa, and the 300% tensile stress E3 of the third bead reinforcing layer is ≥12 MPa, and E1 < E2 < E3.

[0117] 3) Width gradient, see attached document. Figure 2 :

[0118] 3.1) The ratio of the width W1 of the first reinforcing layer 5 to the edge radius R of the rim 10 is 1-1.2;

[0119] 3.2) The ratio of the width W2 of the second reinforcing layer 6 to the width W1 of the first reinforcing layer 5 is 1.5-2;

[0120] 3.3) The ratio of the width W3 of the third reinforcing layer 7 to the width W2 of the second reinforcing layer 6 is 1.5-2.

[0121] 4) Optional thickness gradient:

[0122] The thickness of the innermost first reinforcing layer 5 is b1, and the thickness of the nth reinforcing layer is b. n b n Independent satisfaction: b1×s n-1 The thickness coefficient s is 0.2-0.7;

[0123] Optionally, when the composite material contains three reinforcing layers, the thickness ratio of the first reinforcing layer 5 to the second reinforcing layer 6 to the third reinforcing layer 7 is (5-6):(2-3):(1-1.5).

[0124] (2) Sidewall rubber 8, including abrasion-resistant rubber with a Shore A hardness of 68°-74°, a 300% tensile stress ≥15MPa, and a thickness of 1.5-2.5mm; the abrasion-resistant rubber includes one or more of natural rubber, butyl rubber, fluororubber, hydrogenated nitrile rubber and polyurethane rubber, preferably combined with reinforcing agents to obtain the required performance parameters.

[0125] (3) Triangular rubber 2 and steel wire ring 1, refer to the attached document. Figure 2 :

[0126] The triangular rubber 2 is located at the top of the steel wire ring 1, and the steel wire ring 1 and the triangular rubber 2 are covered by the carcass ply 3 to form an integral structure, wherein:

[0127] Triangle rubber 2 uses high modulus rubber material with a Shore A hardness of 88°-94°;

[0128] The ratio of the height H of the triangular rubber 2 to the diameter D of the steel wire ring 1 satisfies:

[0129] The ratio of the height difference H2 between the top of the triangular rubber 2 and the rim to the rim height H1 is 1:(4-9);

[0130] The high-modulus rubber compound includes one or more of high-hardness nitrile rubber, high-hardness hydrogenated nitrile rubber, polyurethane compound, and silicone rubber, preferably combined with reinforcing agents to obtain the required hardness and other parameters.

[0131] Furthermore, the ratio of the total thickness B1 of the bead reinforcement and sidewall rubber 8 to the total thickness B2 of the top skeleton material of the triangular rubber 2 satisfies the following condition:

[0132] The top skeleton material of the triangular rubber 2, namely the skeleton layer at the top of the triangular rubber 2, includes the front carcass cord, the back carcass cord, and the bead reinforcement layer 4.

[0133] (4) The bead reinforcement layer 4 extends upward from the bottom of the wire ring 1 outside the carcass ply 3. The density of the skeleton cord of the bead reinforcement layer 4 is less than that of the carcass ply 3.

[0134] (5) Bead adhesive 9, starting from the bottom of the high-durability gradient reinforced composite material, surrounds the bead reinforcement layer 4 and / or the carcass ply layer 3. Preferably, the bead adhesive 9 starts from the bottom of the third reinforcement layer 7 and covers at least the bottom of the entire bead structure.

[0135] The method for forming the high-durability aircraft tire bead structure includes the following steps:

[0136] Step 1: Wrap the steel wire ring 1 and the triangular rubber 2 through the carcass ply 3, including:

[0137] 1.1) Lay the reverse-wrapped fabric layer by layer on the aircraft tire forming equipment;

[0138] 1.2) Install the steel wire ring 1 and triangular rubber 2 at the designated position, and reverse the curtain fabric by hand or by reverse wrapping device;

[0139] 1.3) Cover the front-covering curtain with the back-covering curtain;

[0140] Step 2: Apply the bead reinforcement layer 4 from the bottom of the wire ring 1 upwards to the outside of the carcass ply 3. The density of the skeleton cords in the bead reinforcement layer 4 is less than the density of the carcass ply 3.

[0141] Step 3: Attach the high-durability gradient reinforced composite material to the side of the bead reinforcement layer 4 facing the edge of the rim 10. The high-durability gradient reinforced composite material, from the bead adhesive 9 towards the edge of the rim 10, sequentially includes a first reinforcement layer 5, a second reinforcement layer 6, and a third reinforcement layer 7, comprising:

[0142] 1) Outside the bead reinforcement layer 4, the first reinforcement layer 5 is attached upward from the corresponding position at the top of the wire bead 1; the first reinforcement layer 5 is preferably an arc-shaped strip film, with the thickness gradually decreasing from the middle to both ends of the film. The arc-shaped strip film can be symmetrical or asymmetrical in configuration, which can better fill the recessed area on the outside of the bead reinforcement layer 4.

[0143] 2) On the outside of the first reinforcing layer 5, start from the corresponding position in the middle of the wire ring 1 and stick the second reinforcing layer 6 upwards; on the basis of the first reinforcing layer 5, the second reinforcing layer 6 can be a film of uniform thickness;

[0144] 3) Outside the second reinforcing layer 6, at or near the starting position of the second reinforcing layer 6, the third reinforcing layer 7 is pasted upwards; the third reinforcing layer 7 can be a film of uniform thickness;

[0145] Step 4: Adhede the sidewall adhesive 8 to the outside of the high-durability gradient reinforced composite material. The sidewall adhesive 8 is adhered from top to bottom relative to the third reinforcing layer 7, preferably from the tire shoulder downwards.

[0146] Step 5: Starting from the bottom of the high-durability gradient reinforced composite material, cover the bead adhesive 9 around the bead reinforcement layer 4 and / or the carcass ply layer 3. Preferably, the bead adhesive 9 starts from the bottom of the third reinforcement layer 7 and covers at least the bottom of the entire bead structure.

[0147] Example 1

[0148] The high-durability aircraft tire bead structure of this embodiment includes: a steel wire bead, a triangular rubber layer, a carcass ply, a bead reinforcement layer, a sidewall rubber layer, a bead reinforcing rubber layer, a bead rubber layer, and a rim, wherein:

[0149] (1) The bead reinforcement is composed of a high-durability gradient reinforced composite material and is positioned between the bead and the rim edge. The high-durability gradient reinforced composite material includes three sequentially stacked reinforcing layers. The rubber composition of the first, second, and third reinforcing layers is basically the same. From the bead towards the rim edge, the carbon black reinforcing agent content gradually increases. The carbon black content ratio of the first, second, and third reinforcing layers is 4:5:6, which results in a gradual increase in hardness and modulus from the first to the third reinforcing layer. Each reinforcing layer meets the requirements of tensile strength ≥20MPa and elongation at break ≥450%.

[0150] 1.1 The first reinforcing layer has an arc-shaped configuration, a Shore A hardness A1 of 55°, a 300% constant tensile stress E1 of 8MPa, a width of 25mm, and a thickness of 5.5mm at the top of the arc; the ratio of the thickness of the first reinforcing layer to the radius R of the rim edge is 1.1.

[0151] 1.2 The second reinforcing layer has a Shore A hardness of 60°, a 300% constant tensile stress of 10 MPa, a width of 40 mm, and a thickness of 2.5 mm.

[0152] 1.3 The third reinforcing layer has a Shore A hardness of 66° (A3), a 300% tensile stress of 13 MPa (E3), a width of 60 mm, and a thickness of 1.2 mm.

[0153] (2) Sidewall rubber, Shore A hardness 72°, 300% tensile stress ≥15MPa, thickness 1.8mm; the total thickness B1 of bead reinforcement rubber and sidewall rubber is 11mm;

[0154] (3) Triangular rubber and steel wire ring, wherein the Shore A hardness of the triangular rubber is 90°;

[0155] The ratio of the height H of the triangular rubber to the diameter D of the steel wire ring is:

[0156] The ratio of the height difference H2 between the top of the triangular rubber and the rim to the rim height H1 is 1:7;

[0157] The total thickness B1 of the bead reinforcement and sidewall rubber is the ratio of the total thickness B2 of the top skeleton material of the triangular rubber. It is 0.85.

[0158] (4) Bead reinforcement layer, which extends from the lower tire side to the bottom of the wire bead, and the density of the skeleton cord of the bead reinforcement layer is less than the density of the carcass cord.

[0159] (5) Bead rubber, starting from the bottom of the third reinforcing layer, wraps around the outer side of the bottom of the bead and the bead reinforcing layer, covering the bottom of the entire bead structure.

[0160] The steps of the high-durability aircraft tire bead structure forming method include:

[0161] The method for forming the high-durability aircraft tire bead structure includes the following steps:

[0162] Step 1: The steel wire rings and triangular rubber are wrapped into a whole structure through the carcass ply, including:

[0163] 1.1) Lay the reverse-wrapped fabric layer by layer on the aircraft tire forming equipment;

[0164] 1.2) Install steel wire rings and triangular rubber at the designated positions, and reverse wrap the curtain fabric using the reverse wrapping device;

[0165] 1.3) Wrap the front-covering curtain fabric over the back-covering curtain fabric to form the overall structure described above;

[0166] Step 2: Apply the bead reinforcement layer to the outside of the carcass ply, starting from the bottom of the wire bead and moving upwards. The density of the skeleton cords in the bead reinforcement layer is less than that in the carcass ply.

[0167] Step 3: Sequentially attach the first reinforcement layer, the second reinforcement layer, and the third reinforcement layer to the side of the tire bead reinforcement layer facing the rim edge, including:

[0168] 1) Outside the bead reinforcement layer, the first reinforcement layer is applied in an arc-shaped strip starting from the top of the wire bead at the same height as the bead;

[0169] 2) Outside the first reinforcing layer, starting from the middle of the wire ring at the same height, paste the second reinforcing layer of uniform thickness upwards;

[0170] 3) Outside the second reinforcing layer, at the same height as the starting position of the second reinforcing layer, begin to paste the third reinforcing layer of uniform thickness upwards;

[0171] Step 4: On the outside of the third reinforcing layer, attach the sidewall adhesive from the shoulder downwards;

[0172] Step 5: Starting from the bottom of the third reinforcing layer, wrap the tire carcass ply and bead reinforcement layer around the bottom of the bead ring with bead adhesive, covering the bottom of the entire bead structure.

[0173] Examples 2-3

[0174] The main difference between Examples 2-3 and Example 1 is that the hardness of each reinforcing layer, the 300% constant tensile stress, and the ratio of reinforcing agents between each layer are adjusted.

[0175] Examples 4-5

[0176] The difference between Examples 4-5 and Example 2 is that the width and thickness of each reinforcing layer, the hardness and thickness of the sidewall rubber, and the hardness of the triangular rubber are adjusted.

[0177] Comparative Examples 1-3

[0178] The difference between Comparative Examples 1-3 and Example 2 is that the bead reinforcement adhesive uses only a single reinforcing layer.

[0179] The main parameters of Examples 1-5 and Comparative Examples 1-3 are shown in Table 1:

[0180] Table 1. Main parameters of Examples 1-5 and Comparative Examples 1-3

[0181]

[0182] Test methods and results

[0183] 1. Durability test

[0184] Examples 1-5 and Comparative Examples 1-3 were conducted under rated conditions according to CTSO-C62e "Aircraft Tires". The test results are as follows:

[0185] The tire bead products of Examples 1-5 all passed 60 takeoff tests and met airworthiness standards. Among them, the tire bead products of Examples 2-5 passed 80 takeoff tests, and the tire bead products were intact after the tests, without delamination, bulges or other problems, demonstrating excellent durability.

[0186] The tire bead in Comparative Example 1 passed only 15 takeoff tests, the tire bead in Comparative Example 2 passed only 45 takeoff tests, and the tire bead in Comparative Example 3 passed only 30 takeoff tests. After the tests, the samples in Comparative Examples 1-3 all had varying degrees of delamination and bulging problems, and could not meet the requirements of airworthiness standards.

[0187] 2. Pressure resistance test

[0188] Water was injected into the tire bead of Examples 1-5 and Comparative Examples 1-3, and the pressure at which the tire ruptured as the internal pressure increased was measured, known as the burst pressure. The pressure at which a conventional aircraft tire ruptured was set to 100, and the values ​​measured in each example and comparative example are expressed as the pressure resistance index. A higher pressure resistance index indicates better pressure resistance; the test results are shown in Table 2.

[0189] Table 2. Pressure resistance test results of Examples 1-5 and Comparative Examples 1-3

[0190]

[0191] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the invention is intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope.

Claims

1. A high-durability aircraft tire bead structure, characterized in that, This includes steel wire rings, triangular rubber, sidewall rubber, bead reinforcement rubber, and bead rubber; A bead reinforcement is provided between the bead rubber and the rim edge. The bead reinforcement is made of a high-durability gradient-reinforced composite material. The high-durability gradient-reinforced composite material has a Shore A hardness of 50°-75°, a tensile stress of ≥5MPa at 100%-300% of its elongation, a tensile strength of ≥20MPa, and an elongation at break of ≥450%. In the thickness direction, the high-durability gradient-reinforced composite material has a hardness gradient and a modulus gradient. From the bead rubber towards the rim edge, the hardness and modulus of the bead reinforcement gradually increase.

2. The bead structure as described in claim 1, characterized in that, The hardness gradient and / or modulus gradient of the high-durability gradient reinforced composite material are formed through at least one of the following methods: 1) The high-durability gradient-reinforced composite material includes a reinforcing agent, the content of which is gradient-distributed in the thickness direction; 2) In the thickness direction, the high-durability gradient reinforced composite material forms a sulfurization gradient.

3. The bead structure as described in claim 2, characterized in that, The high-durability gradient-reinforced composite material comprises n reinforcing layers stacked sequentially, where n is an integer greater than 1, and the composite material satisfies at least one of the following conditions: 1) The reinforcing agent content of the innermost first reinforcing layer is C1, and the reinforcing agent content of the nth reinforcing layer is Cn. Cn independently satisfies: C1 × p n-1 The quantity coefficient p is 1.1-2; 2) The Shore A hardness of the innermost first reinforcing layer is A1, and the Shore A hardness of the nth reinforcing layer is An. An independently satisfies: A1 × j n-1 The hardness coefficient j is 1.01-1.5; 3) The 100%-300% constant elongation stress of the innermost first reinforcing layer is E1, and the 100%-300% constant elongation stress of the nth reinforcing layer is En. En independently satisfies E1×k n-1 The modulus coefficient k is 1.05-2.

4. The bead structure as described in claim 1, characterized in that, From the bead seal towards the rim edge, the high-durability gradient reinforced composite material sequentially comprises a first reinforcing layer, a second reinforcing layer, and a third reinforcing layer, satisfying at least one of the following conditions: 1) The Shore A hardness A1 of the first reinforcing layer is 55°-60°, and the constant tensile stress at 100%-300% is 5-10 MPa; 2) The Shore A hardness A2 of the second reinforcing layer is 60°-65°, and the constant tensile stress at 100%-300% is 8-14 MPa; 3) The Shore A hardness A3 of the third reinforcing layer is 65°-70°, and the constant tensile stress is ≥12MPa at 100%-300%.

5. The bead structure as described in claim 4, characterized in that, The bead structure satisfies at least one of the following conditions: 1) The ratio of the width W1 of the first reinforcing layer to the radius R of the rim edge is 1-1.2; 2) The ratio of the width W2 of the second reinforcing layer to the width W1 of the first reinforcing layer is 1.5-2; 3) The ratio of the width W3 of the third reinforcing layer to the width W2 of the second reinforcing layer is 1.5-2.

6. The bead structure as described in claim 4, characterized in that, The ratio of the total thickness B1 of the bead reinforcement and sidewall rubber to the total thickness B2 of the top skeleton material of the triangular rubber meets the following requirements: .

7. The bead structure according to any one of claims 1-6, characterized in that, The sidewall rubber has a Shore A hardness of 68°-74° and a tensile stress of ≥15MPa at 100%-300%.

8. The bead structure according to any one of claims 1-6, characterized in that, The bead structure satisfies at least one of the following conditions: 1) The Shore A hardness of the triangular rubber is 88°-94°; 2) The ratio of the height H of the triangular rubber to the diameter D of the steel wire ring satisfies: ; 3) The ratio of the height difference H2 between the top of the triangular rubber and the rim to the rim height H1 is 1:(4-9).

9. A method for preparing a high-durability aircraft tire bead structure as described in any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Wrap the steel wire rings and triangular rubbers through the carcass ply; Step 2: Apply the bead reinforcement layer to the outside of the tire carcass ply, starting from the bottom of the steel wire bead and moving upwards; Step 3: Attach the high-durability gradient reinforced composite material to the side of the bead reinforcement layer facing the rim edge; Step 4: Apply sidewall adhesive to the outside of the high-durability gradient reinforced composite material; Step 5: Starting from the bottom of the high-durability gradient reinforced composite material, cover the bead reinforcement layer and / or the carcass ply with bead adhesive.

10. The application of a high-durability aircraft tire bead structure as described in any one of claims 1-8, or a high-durability aircraft tire bead structure obtained by the preparation method described in claim 9, in an aircraft tire.

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