JPH04191101A - Tire for aircraft - Google Patents

Abstract

PURPOSE:To make a tire light in weight by specifying the distance between each carcass cord and an inner liner in the direction normal to a carcass in such a way as to be specified times as large as the diameter of each carcass cord, and thereby forming the inner liner from rubber compounds including the specified amount of butyl rubber halides. CONSTITUTION:In a carcass ply 7a1 at the innermost side faced to the bore of a tire 1, the distance (t) between each carcass cord 18 and an inner liner 8 in the direction normal to a carcass 6 is made uniform within a range which is equal to or more than 1/4 of the diameter Q of each cord 18, but is less than 2 times as large as the diameter. By this constitution, the occurrence of cracking is thereby restrained. When crack resistance is thus enhanced, gas permeability can be made low, air sealing performance as well as durability can thereby be enhanced with the inner liner 8 made of rubber compounds containing constituents equal to or more than 60 parts of butyl rubber halides by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an aircraft tire that can reduce tire weight and improve the fuel efficiency of aircraft.

[Conventional technology]

In recent years, radial structure tires have been used in aircraft tires used under high load and high speed conditions to improve structural durability and running performance. As shown in FIG. 7(a), a fabric material in the form of a blind weave is used, in which eight carcass cords arranged parallel to each other are interwoven with thin weft threads B.

However, when such a fabric material is used, as shown in FIG. 7(b), the carcass cord A varies greatly in a zigzag shape in the thickness direction of the braai at the interwoven part of the weft yarn B, and each While increasing the thickness of the braai, the Kerr force cord A locally becomes extremely close to the inner liner C for air sealing attached to the inner surface of the carcass. In particular, for aircraft tires, the amount of radial deflection of the tire under load is 28 to reduce shocks during takeoff and landing, etc.
As a result, the proximal portion E of the carcass cord A becomes a weak point during loading, and cracks and the like tend to occur starting from the proximal portion E.

Therefore, in conventional tires, in order to prevent tire damage caused by the rack, the inner liner C
Natural rubber (NR), which has excellent cut resistance and fatigue resistance,
).

[Problem to be solved by the invention]

However, as is well known, natural rubber (NR) has relatively high gas permeability, so in order to maintain high internal pressure air, such as in aircraft tires, airtight, its thickness is usually 2.
It needs to be 5 mm or more, which poses a problem of increasing the total weight of the tire.

In the present invention, the distance between the carcass cord and the inner liner is set to be at least 1/4 times the diameter of the carcass cord and 2.0 times the diameter of the carcass cord.
The inner liner is basically made of butyl rubber containing 60 parts by weight or more of halogenated butyl rubber, and the inner liner is made of butyl rubber containing 60 parts by weight or more of halogenated butyl rubber. The purpose of the present invention is to provide an aircraft tire that can be made thinner and that can solve the above-mentioned problems.

[Means to solve the problem]

In order to achieve the above object, the aircraft tire of the present invention is folded from the tread part through the sidewall part and around the bead core of the bead part, and at an angle of 75 degrees or more and 90 degrees or less with respect to the tire equator. The carcass includes a carcass consisting of at least one carcass fly arranged with carcass cords, and an inner liner arranged radially inside the carcass and covering the inner surface of the carcass. The distance in the direction perpendicular to the carcass between the inner liner and the carcass cord is 1/4 times or more and 2.0 times or less the diameter of the carcass cord, and the inner liner contains 60 parts by weight or more of halogenated butyl rubber as raw material rubber. It is made of a rubber composition made of butyl rubber.

[Effect]

In this way, the aircraft tire of the present invention makes the distance between the carcass cord and the inner liner uniform within a range of 1/4 or more and 2.0 times or less of the diameter of the carcass cord. Close areas are excluded. Therefore, it is possible to suppress local concentration of stress that acts during loading,
Moreover, since weak points can be eliminated, the occurrence of cracks and the like can be prevented. As a result, it is possible to form the inner liner using butyl rubber, which has low gas permeability, while maintaining the durability of the tire, and its thickness can be significantly reduced.

In addition, in order to improve co-vulcanization and adhesion with the carcass, at least 60% of halogenated butyl rubber is added to the butyl rubber.
It is necessary to mix at least 90 parts by weight, preferably at least 90 parts by weight, to improve adhesion to the carcass.

〔Example〕

Below, an example of the present invention is shown in which the tire size is 46X17R.
Taking the case of No. 20 aircraft tires as an example, explanation will be given based on the drawings.

In FIG. 1, which shows a cross section of a tire mounted on a regular rim R and in a normal internal pressure state where a normal internal pressure is applied, an aircraft tire 1 (hereinafter referred to as tire 1) has a bead core 2.
The tire includes a bead portion 3 through which the tire passes, a sidewall portion 4 that is continuous with the bead portion 3 and extends outward in the tire radial direction, and a tread portion 5 that connects the outer ends of the sidewall portion 4.

Furthermore, there are multiple carcass flies 7 between the bead parts 3 and 3.
A toroidal carcass 6 in which the inside and outside are stacked is placed over a rack, and an inner liner 8 for air sealing is provided on the inside in the radial direction to cover the inner surface of the carcass 6 facing the tire bore H.

In this example, the carcass 6 includes an inner layer 7A consisting of a plurality of pieces, for example, four carcass flies 7a, which are folded around the bead core 2 from the inside to the outside of the tire, and a folded part of the inner layer 7A. The inner carcass fly 7a is made up of an outer layer 7B consisting of a plurality of layers, for example two outer carcass flies 7b, 7b, which are unwound from the outside to the inside of the tire. At both ends of the toroid-shaped body portion 70 leading to the bead portion 3, there is a folded portion 71 that folds around the bead core 2 from the inside of the tire to the outside, and the outer carcass fly 7b is provided at both ends of the toroid-shaped body portion 73. , is provided with an unrolling part 74 unrolled on the outside of the bead core 2.

In addition, the inner and outer carcass flies 7a and 7b each include carcass cords 18 arranged at an angle of 75 degrees to 90 degrees with respect to the tire equator. code 18
They are placed one on top of the other in different directions so that they alternately intersect with the circumferential direction and are tilted.

As the cord 18, organic fiber cords such as rayon, polyester, vinylon, nylon, and aromatic polyamide are used.

In the present invention, in the innermost carcass fly 7al facing the tire bore H, the distance t between the carcass cord 18 and the inner lychee 8 in the direction perpendicular to the carcass 6, as shown in FIG. carcass code 1
8 and the inner surface of the carcass 6 is made uniform within the range of 4 times or more and 2.0 times or less the diameter of the carcass cord 18, eliminating weak points in the strength against tire deformation and preventing the occurrence of cracks, etc. is suppressed. For this purpose, in this example,
Each carcass fly 7 has a novel structure in which carcass cords 18 are arranged flatly without variation in the thickness direction of the fly.

That is, the carcass brief is formed from a sheet body in which a cord arrangement body 20 in which carcass cords 18 are arranged parallel to each other in the same plane without being joined by weft threads is embedded in carcass rubber 19 which is topping rubber.

Therefore, compared to conventional braais using blind-weave fabric materials, the thickness of the braai can be significantly reduced while maintaining the same topping rubber coating thickness, reducing internal heat generation and reducing weight. can be achieved. In addition, the carcass rubber 19 has cut resistance, similar to conventional aircraft tires.
A rubber composition containing natural rubber as a main component, which has excellent fatigue resistance, aging resistance, heat resistance, etc., is used.

In addition, since such a carcass fly 18 eliminates the restraining force caused by the weft threads, it is possible to arrange the carcass cords with high precision within the same plane. There is a risk that the code arrangement will be greatly disturbed. However, the formation became possible by adopting a new means devised by the present inventor. That is, Fig. 4 (
As shown in a) to (b), a cord array body 32 consisting of carcass cords 18 unwound from each bobbin 30 and aligned parallel to each other by a guide 31 is coated with topping rubber 19 to a predetermined thickness in a die 33. Then, the rubber is exposed to form 11 tape-like bodies 35 having a uniform thickness. After that,
The tape-like body 35 is wound spirally on a drum 36 having external dimensions according to the tire size to form a single-layer cylindrical body 37, and a slit 38 on the drum extending in the width direction is formed. A wide and homogeneous sheet-like carcass fly is formed by cutting along the . Note that the guide 31 is connected to the carcass cord 18 as shown in FIG. 4(b).
Guide holes 39 for inserting the carcass cord 18 are formed on the same straight line at equal pitches, for example, in the shape of a block, and the carcass cord 18 is moved downstream of the bobbin 30 and the presser roller 40 by using the tension applied between the bobbin 30 and the presser roller 40. , are arranged parallel to each other within the same plane. The die 33 includes a base body 33A having a rubber chamber 42 that communicates with the rubber extruder 41 and through which the cord alignment body 32 passes, and a base body 33A that is detachably attached to the front and rear ends of the rubber chamber 42 and has a molding hole 43. and a ring material 33B having
The ring material 33B has a hole 43 spaced apart from the cord alignment body 32, so that the ring material 33B has a cross section corresponding to the opening shape of the hole 43 and has a tape shape with the cord alignment body 32 embedded in the center thereof. A body 35 can be formed. Note that the base body 33A is provided with an outlet 42A that communicates with the rubber chamber 42 and takes out excess rubber.

Further, it can also be formed using other means shown in FIGS. 5(a) to 5(b). That is, using a drum 23 in which fitting grooves 22 for positioning for receiving the lower surface of the carcass cords 18 are arranged in parallel, a plurality of supplied carcass cords 18-11 are supported in parallel to each other on the outer peripheral surface of the drum 23. Further, an extrusion-molded topping rubber piece 19A is attached to the outer surface of the topping rubber piece 19A with a uniform thickness, while a similar topping rubber piece 19B is attached to the other side of the cord array 20 based on the outer surface of the topping rubber piece 19A to which the rubber is attached. Attach rubber.

As a result, the carcass cords 18 are arranged parallel to each other in the same plane within the rubber 19 without variation in the thickness direction.

Here, "arranging in the same plane" means 171 points of the diameter of each carcass cord from the reference plane S, as shown in FIG.
Between the upper and lower critical planes S1 and S1 separated by a distance l of 0 times,
This means that each carcass cord 18 is arranged in parallel with its center located, and the distance l is preferably D/12 or less, more preferably D/14 or less.

Further, the diameter is the diameter of the smallest diameter among the circumscribed circles circumscribing the carcass cord 18, and in the present invention,
In order to improve the crack resistance of the innermost carcass fly 7al, the distance is regulated within the above range as described above.

Note that if the distance t is less than 1/4 times the diameter, the carcass cord and the inner liner 8 (described later) are too close to each other, and when the tire is bent and deformed, a cord array is generated, causing cracks and the like. If the diameter exceeds twice the diameter, the tire thickness will increase excessively, leading to an increase in tire weight, and the internal temperature will rise, inducing thermal breakdown of the rubber.

In addition, in the present invention, in order to improve the crack resistance by regulating the distance t, the inner liner 8 is made of a rubber composition made of butyl rubber with low gas permeability and containing 60 parts by weight or more of halogenated butyl rubber as a raw material rubber. This makes it possible to reduce the thickness T of the inner liner 8 to about 1 mm while improving air sealing performance and maintaining durability, thereby reducing the total weight of the tire.

Note that since the halogenated butyl rubber contains halogen as a constituent element, it tends to have a thermal effect when heated to a high temperature, and this tendency becomes more pronounced as the halogen content increases.

Of the raw rubbers, this regular butyl rubber is used as the remaining rubber other than the halogenated butyl rubber.

As shown in FIG. 2, such raw material rubber increases gas permeability as the blending ratio of halogenated butyl rubber decreases, but on the other hand, co-vulcanization with the carcass rubber 19 decreases.

Therefore, in the present invention, the content of halogenated butyl rubber in the raw material rubber is set to 60 parts by weight or more, preferably 90 parts by weight or more. If the content is less than 60 parts by weight, the co-vulcanizability will be excessively reduced and separation with the carcass rubber 19 will tend to occur.

In addition, the raw material rubber may contain well-known additives such as components for improving reinforcing properties such as carbon black; components for improving processability and as a vulcanization aid such as process oil; for example, magnesium oxide and mercaptobenzothiazyl. A tartar such as disulfide (MBTS) which acts as a vulcanization retarder on butyl rubber to prevent rubber burning; a vulcanization accelerator such as zinc white; and a vulcanizing agent such as sulfur may be appropriately blended.

Further, in this embodiment, the bead portion 3 is provided with a bead apex 9 that passes between the main body portion 70 and the folded portion 71 and rises from the bead core 2 in a tapered shape, and is reinforced from the bead portion 3 to the sidewall portion 4. At the same time, a belt layer 10 is provided inside the tread portion 5 at a position radially outward of the carcass 7 via a cut breaker 11 .

The cut breaker ply 11 is, for example, a cut breaker ply arranged such that each cord intersects between the plies.
The tread has a two-layer structure consisting of layers a and lla, and runs along the carcass 6 at the crown portion at the center of the tread, and gradually separates from the carcass 6 on the outside. In addition, in the tire axial direction of the cut breaker 11, the width of W in the tire cross section is 70 to 85.
%, more preferably in the range of about 73 to 78%.

Further, the belt layer 10 is a multilayer body consisting of a plurality of sheets, for example, eight belt braces 10a, and is in contact with the cut breaker 11, and its outer end extends beyond the outer end of the cut breaker 11. At the same time, it is leveled on the slope along the outer surface of the tire. In addition, the belt layer 10 has a width of 7 W in the cross section of the tire.
It has a belt thickness of about 0 to 85%, and by restraining the carcass 7 with a hoop effect, together with the cut breaker 11, it increases tire rigidity and improves running performance.

Note that the shortest distance I7 from the outer end of the belt layer 10 to the tire outer surface is set to about 3 to 15 mm, and the belt cord forming the belt ply 10a is set at an angle of 0 to 30 degrees with respect to the tire equator. They are juxtaposed at an angle.

〔Concrete example〕

A test piece made of a rubber composition that can be used for the inner liner 8 of the present invention (length: 55 mm, width: 55 mm, thickness: 4 mm)
) was prototyped based on the specifications in Table 1, and as physical properties of the test piece, the scorch time TL 2.90% vulcanization time and maximum torque were measured by a rheometer test, and the adhesion to the carcass was examined.

In addition, scorch time TL in rheometer test, 9
0% vulcanization time and maximum torque value are Monsanodo R-1
00 at a measurement temperature of 150°C. The adhesion to the carcass was tested by a method based on JIS K6301 by gluing the carcass rubber and a test piece together and press-vulcanizing them at a pressure of 30 kg/aa at a temperature of 140° C. for 40 minutes.

〔Effect of the invention〕

As shown above, the aircraft tire of the present invention regulates the distance between the carcass cord and the inner liner within a predetermined range, and uses butyl rubber containing 60 parts by weight or more of halogenated butyl rubber for the inner lychee, so it has excellent durability. The inner liner can be made thinner while maintaining cracking properties and air sealing properties, and weight reduction can be promoted without impairing tire performance.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing one embodiment of the present invention, Fig. 2 is a partial cross-sectional view illustrating the distance between the carcass cord and the inner liner, and Fig. 3 is a graph showing the relationship between the halogenated butyl rubber content and gas permeability. 4(a) and (b) are diagrams illustrating one means of carcass fly formation, and FIG. 5 (J
1) and (b) are diagrams explaining other means of carcass fly formation, FIG. 6 is a diagram explaining carcass fly, and FIG.
Figures (a) and (b) are diagrams explaining the prior art. 2...Bead core, 3...Bead part, 4-, -side wall part, 5-, -tread part, 6...Carcass, 7.7 a, 7 b ---Carcass fly, 8...
--- Inner liner, 18 --- Carcass cord. Patent Applicant Sumitomo Rubber Industries Co., Ltd. Agent Patent Attorney Masaaki Naemura Figure 1 Figure 2 Figure 3 Hello F-5 Iko, Ga 1. Yu...Yu-containing wheel (coulometric section) 5th L: (b) Fig. 5 (a) Fig. 6 Fig. 7 (a)

Claims (1)

[Claims] 1 Consists of at least one carcass fly, which is folded back from the tread part through the sidewall part and around the bead core of the bead part, and the carcass cords are arranged at an angle of 75 degrees or more and 90 degrees or less with respect to the tire equator. a carcass; and an inner liner disposed radially inside the carcass and covering an inner surface of the carcass;
The carcass has a distance between the carcass cord and the inner liner in a direction perpendicular to the carcass, and the inner liner is made of raw rubber. An aircraft tire formed from a rubber composition made of butyl rubber containing 60 parts by weight or more of halogenated butyl rubber.