JPS6349502A - Tire for aeroplane - Google Patents

Abstract

PURPOSE:To improve the durability by using the specific organic fiber cords having a relatively low elastic modulus for the cords of a carcass, belt layer, and a reinforcing layer and arranging the reinforcing layers at the prescribed positions, thus preventing the carcass at the tire bead part from being damaged. CONSTITUTION:The cords of a carcass 5 consisting of a plurality of carcass plies 2-4 which are arranged on the periphery of a bead core 1 and a belt layer 6 arranged on the outside are arranged at the angles of 60-90 deg. and 0-30 deg. with respect to the tire equator plane. In the region surrounded by the carcass plies 2 and 3 and the turned-over parts 2a and 3a, a bead apex 9 extended to a prescribed height Hf is installed. Further, a reinforcing layer 10 extending in the side wall direction is installed between the bead apex 9 and the carcass 5, protecting the periphery of the bead core 1. The organic fiber cord having a tensile modulus of 5,000kg/mm<2> or less is used for the cords of the carcass 5, belt layer 6, and the reinforcing layer 10.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has sufficient load capacity, reduces damage to the bead portion caused by repeated large deformations during aircraft travel, and effectively reduces impact on the aircraft body. This invention relates to aircraft tires that can be used to reduce stress.

[Conventional technology]

Recently, the development of aircraft has been remarkable, and as the aircraft weight and flight speed have increased, the tires are required to withstand high loads and high speeds as well as safe landings. In addition, the following characteristics are required for aircraft tires that differ from general tires.

b) It is essential for aircraft tires to reduce the impact when the aircraft lands on the runway, stop the aircraft safely, and facilitate takeoff. From this perspective, the structural design of the tire, Select tire reinforcement materials.

Aircraft tires are designed to have a large amount of deflection under load, for example around 28% to 35%, in order to effectively cushion the impact of the aircraft and ensure safe takeoff and landing.
Therefore, tires, etc. that can withstand large repeated deformations 3
It is necessary to select the materials for the structure and reinforcing materials, and therefore, conventionally, for this type of tire,
A cross-brie structure in which the carcass cords are configured to cross each other between brais is often used. Tires with this type of structure have low rigidity of the tread OH due to the direction in which the carcass cords are arranged, which is unfavorable in terms of wear resistance and heat generation.

Furthermore, in the conventional tire, centrifugal force accompanying high speed rotation of the tire causes temporary or permanent so-called tire growth in which the central part of the trend protrudes, and the durability of the tire is unsatisfactory. Therefore, we adopted a so-called radial structure in which carcass cords are arranged in the tire's radial direction, and by placing a belt layer on the inside of the tread in which highly elastic cords are arranged at a relatively shallow angle in the circumferential direction of the tire, we increase the rigidity of the tread. radial tires were used.

[Problem that the invention seeks to solve]

However, this type of radial tire has low lateral rigidity because its carcass cords are arranged in the radial direction.
The amount of deformation becomes relatively large.

As a result, the tire sidewall collapses onto the upper side of the rim flange, causing strong compressive stress to occur in the lower region of the sidewall and the folded portion of the carcass ply. Further, around the bead core, the carcass ply is subjected to extensional strain due to repeated deformation, and the carcass is likely to be damaged or peeled from the bead core in this area, leading to breakage of the bead portion.

Conventionally, tires for heavy vehicles such as trunks and buses have a structure in which the reinforcing layer A completely covers the bead core B and the bead apex C, as shown in FIG. A structure in which a reinforcing layer ESF is placed adjacent to the outside of the folded part has been adopted, but when large deformations occur such as in aircraft tires,
These structures cannot maintain sufficient performance.

This invention is a tire with a cross-brie structure, and by setting the elastic modulus of the cords of the carcass and the cords of the belt layer within a specific range and arranging a reinforcing layer, it is possible to improve wear resistance and reduce heat generation and tire growth. It is an object of the present invention to provide an aircraft tire that suppresses damage to the carcass around the bead core and enhances the effect of mitigating shock during takeoff and landing.

[Technical means to solve problems]

In this invention, both ends are folded back and locked around a pair of left and right bead cores, and the cord is fixed at an angle of 60° to the tire equatorial plane.
A carcass arranged at an angle of 90" and a cord arranged outside the carcass at an angle of 0° to 30" with respect to the tire equatorial plane.
A belt layer arranged at a cord angle of ゛, a bead apex arranged in an area surrounded by the carcass and its folded part, and a belt layer covering and protecting the bead core and extending in the sidewall direction between the bead apex and the carcass. a reinforcing layer, the carcass, the belt layer and the cord of the reinforcing layer all have a tensile modulus of 50.
This is an aircraft tire characterized by being made of an organic fiber cord weighing less than 0.00 kg/Tsuru.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the right half of the tire of the present invention. In FIG. A carcass 5 constituted by at least one or more carcass plies 4 that wrap around the carcass ply 1 from the outside to the inside with the ends folded back and locked.
Equipped with. Further, a belt layer 6 made of organic fiber cord is arranged on the outside of the crown portion of the carcass 5. The cords of the carcass 5 are arranged at an angle of 606 to 90 degrees with respect to the tire equatorial plane, but in particular, in order to increase the lateral rigidity of the tire,
The braais can be arranged to intersect alternately in the range of 80° to 80°.

Organic fiber cords with a tensile modulus of elasticity of carcass 5 and bell 1-rfi 6 of 5000 kg/vm or less, preferably 1000 kg/vm or less, are used. The carcass 5 and the belt layer 6 are required to have sufficient bending fatigue resistance under large deformations. Due to the difference in stiffness near the boundary between both ends of
In order to prevent ply separation between the carcass and belt layer,
For both the carcass ply cord and the belt layer cord, organic fiber cords with a relatively low elastic modulus, particularly 5000 kg/w2 or less, are used. This increases the bending durability, and by bringing the elastic modulus of the carcass cord and the belt layer cord close to each other, it is possible to effectively suppress stress concentration at the ends of the bell.

Here, as the organic TA fiber cord used as the carcass cord and the belt layer cord, rayon, polyester, vinylon, aramid, and nylon can be used as shown in the first example. In addition, the carcass cord and the belt layer cord are made of substantially the same material, for example, by using nylon 66 for both the carcass cord and the belt layer cord, repeated impacts received from the tread portion of the belt layer are effectively absorbed and alleviated by the carcass. Damage to the tread can be prevented.

A bead apex 9 extending to a height Hf of 5% to 75% of the tire cross-sectional height H is provided in a region surrounded by the first carcass 2.3 and its folded parts 2a and 3a. This bead apex 9 has the function of increasing the lateral rigidity of the tire side part, and if the height is less than 5%, these functions are insufficient, but if it exceeds 75%, the balance of the tire will deteriorate! @Relaxation effect is inhibited. The dynamic elastic modulus (E*) of Bead Apex 9 was measured using a Harumoto Seisakusho viscoelastic spectrometer at a temperature of 70°C, an initial strain of 10%, a vibration of 2.0%, and a frequency of 10 Hz over a 4 fl width x 30 fi length. × 200 kg f/QJ ~ 1 as measured using a 2-day thick sample
500 ktr f/crl, preferably 300 kg
f/- or more. By using the bead apex 9 having such characteristic values, it is possible to maintain the lateral rigidity of the tire during high speed rotation.

Further, a reinforcing layer 10 is arranged to cover and protect the bead core 1 and extend in the sidewall direction between the bead apex 9 and the carcass 5, that is, between the bead apex 9 and the innermost carcass ply 3. This reinforcing layer 10 is applied to the bead core 1 due to repeated deformation of the tire.
This prevents severe damage to the carcass 5 in this area due to strong elongation of the carcass 5 around the bead core and abrasion between the hard bead core and the bead core. Furthermore, the rigidity of the carcass 5 is strengthened to reduce the collapse of the lower area of the sidewall toward the rim flange 11 (indicated by a broken line in FIG. 2) under load, and to effectively prevent damage to the carcass 5 in this area. . Therefore, it is desirable that the reinforcing layer 10 is composed of two or more plies arranged so that the cords intersect between the plies at a cord angle of 0° to 90", preferably 30° to 45" with respect to the tire circumferential direction. .

In addition, the height He to the top 410a of the reinforcement r510 is preferably set at a position higher than the upper end of the folded part 2a of the carcass within a range of 20 to 60% of the tire cross-sectional height H from the bead base. 1'f! The other end 10b of the bead core 1 is folded back around the bead core 1 and is locked near the upper end of the bead core 1 or at the lower side of the bead core 1. In addition? l
Since the strong layer 10 does not form a step due to rigidity between the adjacent carcass ply 3, the tensile modulus is 5000 kg/- or less, preferably 1000 kg/- or less, and the carcass is further bonded to the carcass ply 3. The reinforcing layer 10 is preferably a cord made of the same material as the above-mentioned organic fiber cord, such as nylon, polyester, or rayon cord, embedded in rubber having a double X modulus (E*) of 70 to 110 kir/-. It is preferably constructed by embedding cords of the same material as the carcass 5 in layers.

By setting Tand of the embedded rubber in the range of 0.10 to 0.25, heat generation is suppressed and the carcass 5
The effect of reducing damage becomes even higher.

Here, the complex modulus of elasticity E* and Tand are measured by the same measuring method as the bead apex.

Furthermore, by arranging the cushion rubber 7 whose thickness gradually decreases both inside and outside around the bell l-N614 portion between the belt layer 6 and the carcass 5 below both ends of the belt layer 6, stress concentration at both ends of the belt 16 can be effectively reduced. It can be absorbed and relaxed. Cushion rubber 7 has a 300% modulus of 70~
A weight range of 150 kg/- is used.

Further, in the present invention, the modulus of the topping rubber of the carcass 5 and the belt layer 6 is a relatively soft rubber corresponding to the elastic modulus of the cord, for example, a 300% modulus of 80 to 16.
A range of 0 kg/cd is used.

EXAMPLE Aircraft tires with a tire size of 26 x 6.6 had the basic structure shown in FIG. 1, and tires with various specifications shown in Table 2 were manufactured as prototypes, and the durability of each tire was evaluated.

Durability test is TSO-C62c specified by the National Civil Aviation Administration standard.
The number of take-offs and taxi simulations leading to failure according to the test is shown.

In Table 2 showing the evaluation results, it is recognized that all of the Examples meet the standards of the durability test.

〔Effect of the invention〕

As described above, the aircraft tire of the present invention has a carcass cord, a belt layer, and a reinforcing layer cord.
Table note 1) In the TSO-C62c test specified by the National Civil Aviation Administration standards, 61 times indicates the specified number of times, and +4 indicates the number of tick-offs at the bottom of 1.5 times the weight.

Note 2) Ratio to tire cross-sectional height.

In addition to using a specific organic fiber cord with a relatively low modulus of elasticity, we also placed a reinforcing layer around the bead core and between the inner carcass and bead apex. By preventing damage, aircraft tires with excellent durability can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a right half sectional view of a tire showing an embodiment of the present invention, FIG. 2 is a schematic sectional view of a bead section, and FIGS. 3 and 4 are sectional views of a bead portion of a conventional tire. T...-tire, 1--bead core, 2.3.4
- Carcass ply, 5 - Carcass, 6...
-Belt layer, 7--cushion rubber, 9--bead apex, io-m strong i. Patent applicant Sumitomo Rubber Industries Co., Ltd. Agent Patent attorney Masaru Naemura 7m

Claims (3)

[Claims] (1) Both ends are folded back and locked around a pair of left and right bead cores, and the cord is 60° to 90° to the tire equatorial plane.
A carcass arranged at an angle of a bead apex disposed, and a reinforcing layer that covers and protects the bead core and extends in the sidewall direction between the bead apex and the carcass, and the cords of the carcass, the belt layer, and the reinforcing layer are all tensile. Elastic modulus is 5000k
An aircraft tire characterized by being made of an organic fiber cord of g/mm^2 or less. (2) The tensile modulus of the carcass cord is 1000 kg/
The aircraft tire according to claim 1, which has a diameter of mm^2 or less. (3) The aircraft tire according to claim 1, wherein the upper end of the reinforcing layer is in a range of 15 to 60% of the tire cross-sectional height.