JPH05294106A - Radial tire for aircraft - Google Patents

Abstract

PURPOSE:To provide a radial tire for aircraft in which separation of joint face of longitudinal both ends of a wavy cord protective layer can be prevented. CONSTITUTION:A wavy cord protective layer 28 comprises a plural number of wavy cords 30 coated with coating rubber 32, and the center line W of amplitude of the wavy cord 30 extends along the circumferential direction of a tire. Substantially the same rubber 33 as the coating rubber 32 of the wavy cord protective layer 28 is set between the longitudinal both ends of the wavy cord protective layer 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radial tire for aircraft used in aircraft such as jet passenger aircraft.

[0002]

2. Description of the Related Art In recent years, radial tires have come to be used in aircraft such as jet passenger aircraft. Since this radial tire for aircraft is used at a high internal pressure, the pressure on the ground contact surface is high. Therefore, when taking off and landing at high speed or traveling in an airport, the tread portion may be injured by a projection or the like falling on the road surface. In particular, when the external damage is large, the belt disposed inside the tire portion in the tire radial direction is also damaged, and rehabilitation by replacing the tire portion becomes difficult.

As a radial tire for aircraft to improve this, as shown in FIGS. 7 (A) and 7 (B), a plurality of wavy cords 72 having an amplitude center line W arranged along the tire circumferential direction are provided. There is known a radial tire for aircraft in which a corrugated cord protective layer 70 covered with a coating rubber 74 is arranged between a tread portion and a belt (Japanese Patent Laid-Open No. Sho 5).
7-201704).

The corrugated cord protection layer 70 has both longitudinal ends thereof joined to each other by butting. Therefore, in this radial tire for aircraft, the thickness of the connecting surfaces at both longitudinal ends of the wavy cord protective layer 70 becomes uneven, and the tire vibrates in the tire radial direction during traveling. In order to reduce this, the joint surface T is inclined with respect to the tire circumferential direction.

[0005]

However, although the coating rubbers are adhered to each other on the bonding surfaces at both ends in the longitudinal direction of the wavy cord protective layer, the abutting surfaces of the wavy cords or the abutting of the wavy cords and the coating rubbers. The faces are not glued together. For this reason, if the cross sections of the longitudinal ends of the wavy cord do not match, the unbonded portions of the coupling face may be continuous on the bonding faces at the longitudinal ends of the wavy cord protective layer. For this reason, the bonding force of this bonding surface becomes low, and there is a risk of peeling.

In view of the above facts, an object of the present invention is to obtain a radial tire for an aircraft capable of preventing the separation of the bonding surfaces at both longitudinal ends of the wavy cord protective layer.

[0007]

A radial tire for an aircraft according to claim 1 of the present invention comprises plies made of cords arranged in parallel with each other, and at least one ply is arranged around a pair of bead cores from an inner side in the tire axial direction. A toroidal carcass having a folded-back portion that is rewound to the outside, and a belt made of a plurality of plies arranged between the carcass and the tread of the tire, and between the belt and the tread, an amplitude center line is provided. A radial tire for an aircraft having a wavy cord protective layer in which a plurality of wavy cords arranged along the tire circumferential direction are coated with a coating rubber, and the longitudinal ends of the protective layer are joined together by butting. It is characterized in that substantially the same rubber as the coating rubber is disposed between both ends in the longitudinal direction of the protective layer.

The aircraft radial tire according to claim 2 of the present invention is characterized in that, in the aircraft radial tire according to claim 1, the wavy cord is made of an organic fiber.

[0009]

In the radial tire for aircraft according to the first aspect of the present invention, since substantially the same rubber as the coating rubber of the wavy cord is arranged between the longitudinal ends of the wavy cord protection layer, the abutting surface of the wavy cord is The abutting surfaces of the cords or the corrugated cord and the coating rubber do not come into contact with each other, and the longitudinal ends of the corrugated cord protective layer are bonded to each other. Therefore, even if the cross-sections of both ends of the wavy cord in the longitudinal direction of the wavy cord protective layer do not coincide with each other in the cross-sections of the wavy cord, the entire bonding face is reliably bonded by the rubber. Therefore, the bonding force of the bonding surface is not reduced, and the bonding surfaces at both longitudinal ends of the wavy cord protective layer can be prevented from peeling off.

The rubber disposed between the longitudinal ends of the corrugated cord protection layer need not be the coating rubber of the corrugated cord, and the coupling between the longitudinal ends of the corrugated cord protection layer is the coupling between the rubber and the rubber. If so, other rubber that can adhere to the coating rubber may be used.

The aircraft radial tire according to claim 2 of the present invention is the same as the aircraft radial tire according to claim 1, wherein the corrugated cord protective layer cord is Kevlar (trade name: manufactured by Du Pont), nylon, Since it is made of organic fiber such as polyester, the wavy cord diameter is thicker than that of metal fiber. This is because it is necessary to make the cross-sectional area of the organic fiber cord larger than that of the metal fiber cord in order to make the cords have the same breaking strength. Then, the adhesive surface between the coating rubbers between the both ends of the wavy cord protective layer in the longitudinal direction becomes small.

Therefore, by arranging substantially the same rubber as the coating rubber of the wavy cord between both ends of the wavy cord protection layer in the longitudinal direction, the entire surface of both ends of the wavy cord protection layer in the longitudinal direction is irrespective of the sectional area of the wavy cord. Can be reliably bonded by bonding rubber to rubber. For this reason, even if the wavy cord is an organic fiber, the bonding force of the bonding surface does not decrease, and peeling of the bonding surface at both longitudinal ends of the wavy cord protective layer can be prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a radial tire for an aircraft of the present invention will be described below with reference to FIGS.

As shown in FIG. 2, the carcass 11, 12 of the aircraft radial tire 10 (tire size 46 × 17R20) is composed of carcass plies in which carcass ply cords are radially arranged around the tire rotation axis. Both ends of the carcass 11, 12 in the tire width direction are folded back from the tire width direction inner side to the outer side around a ring-shaped bead core 14 arranged on the tire radial inner side of the aircraft radial tire 10. , And folding portions 11A and 12A, respectively.

Carcasses 17 and 19 are arranged on the outer side of the carcass 12 in the radial direction of the tire (the upper side in FIG. 2), and both end portions of these carcass 17 and 19 in the tire width direction are arranged around the bead core 14, respectively. It is folded back from the inner side in the tire width direction toward the outer side in the tire width direction to form folded portions 17A and 19A, respectively.

Carcasses 15 and 16 are arranged on the outer side of the carcass 19 in the tire radial direction (upper side in FIG. 2), and both end portions of these carcasses 15 and 16 in the tire width direction are arranged around the bead core 14, respectively. The tire is folded back from the tire width direction outer side toward the tire radial direction inner side (lower side in FIG. 2) to form folded-back portions 15A and 16A, respectively.

A cross belt 18 is arranged along the carcass 16 on the outer side in the tire radial direction of the carcass 16 (the upper side in FIG. 2), and the top is arranged on the outermost side in the tire radial direction of the aircraft radial tire 10. The rubber 27 is reinforced.

A circumferential belt 20 is arranged on the outer side (upper side in FIG. 2) of the cross belt 18 in the tire radial direction, and both end portions 20A of the circumferential belt 20 in the tire width direction are arranged.
Is on the outer side (that is, wider) in the tire width direction than both ends 18A of the cross belt 18 in the tire width direction.

As shown in FIG. 3, the cord 31 of the circumferential belt 20 runs along the tire circumferential direction (arrow S direction) and prevents the standing wave of the aircraft radial tire 10.

Cross belts 21, 22 and 24 are respectively arranged on the outer side (upper side in FIG. 2) of the circumferential belt 20 in the tire radial direction.
2 and 24 tire width direction both ends 21A, 22A and 24A
Are arranged on the inner side in the tire width direction with respect to the circumferentially arranged belts 20, respectively, and the crossed belts on the outer side in the tire radial direction have both ends in the tire width direction on the inner side (that is, narrow width) in the tire width direction.

As shown in FIG. 3, the cross belts 22, 2
The cords 23 and 25 of 4 are inclined at 22 degrees in different directions with respect to the circumferential direction of the tire and intersect each other, so that the top rubber 27 of the radial tire 10 for aircraft is reinforced. Is becoming

Further, as shown in FIG. 4, the cross belt 1
Each of 8 and 21 is a four-layer hold belt. That is, the first layer A, the second layer
The layers B and the third layer C are formed, and the tire width direction both ends of the first layer A enclose the second layer B and the third layer C to form the tire width direction both ends D of the fourth layer. Further, the central portion E in the tire width direction of the fourth layer is composed of a narrow belt.

As shown in FIG. 5, the angle θ of the cord 34 of the cross belt 18 with respect to the tire circumferential direction (arrow S direction) is 24 ° to the left in the first layer A and 22 to the right in the second layer B, respectively. 22 ° to the left in the third layer C, 24 ° to the right in the tire width direction ends D of the fourth layer, and 22 ° to the right in the tire width direction central portion E of the fourth layer. In the tire circumferential direction of the cord 34 of the cross belt 21 (arrow S
Angle θ to the left side in the first layer A, 18 ° to the right side in the second layer B, 18 ° to the left side in the third layer C, and right side in the tire width direction both ends D of the fourth layer. To 1
8 °, 20 ° to the right at the central portion E of the fourth layer in the tire width direction
It is said that.

As shown in FIG. 2, the cross belt 24 is
The belt is the outermost belt in the tire radial direction, and the corrugated cord protection layer 28 is disposed between the cross belt 24 and the top rubber 27. The wavy cord protection layer 28 has both end portions 28A in the tire width direction. The cross belt 24 is located on the inner side (that is, narrower) in the tire width direction than both end portions 24A in the tire width direction.

As shown in FIG. 1A, the corrugated cord protection layer 28 has a structure in which a plurality of corrugated cords 30 are covered with a coating rubber 32, and the amplitude center line W thereof is in the tire circumferential direction. (Direction of arrow S in FIG. 1 (A))
Are arranged along. Further, the joint surfaces T at both ends in the longitudinal direction of the wavy cord protective layer 28 are inclined at a predetermined angle α with respect to the amplitude center line W (tire circumferential direction). Length (K in Fig. 3)
And the joint surface T is not concentrated in a narrow range in the tire circumferential direction, the radial tire for aircraft 10 does not vibrate significantly in the tire radial direction on the joint surface T during traveling.

As shown in FIG. 1B, the wavy cord protection layer 28 is provided between the longitudinal ends of the wavy cord protection layer 28.
A rubber 33 that is substantially the same as the coating rubber 32 of FIG. This rubber 33 is provided in advance with the corrugated cord protection layer 2
8 is provided with a thickness G and a width L at positions that cover both longitudinal end portions 28B and 28C of the rubber cord 8. By bonding the longitudinal end portions 28B and 28C of the corrugated cord protective layer 28 to each other, the rubber 33 is formed into a corrugated cord. The protective layer 28 is interposed between both ends in the longitudinal direction.

Further, as shown in FIG. 6, the main strain of the joint surface T when the working internal pressure of the tire is filled is that the thickness 2G of the rubber 33 interposed between the longitudinal ends of the wavy cord protective layer 28 increases. The thickness G of the rubber 33 should be 0.1 mm or more, because it gradually decreases and when 0.005 mm is set to 100, 0.1 mm is 50% less than this.

By interposing the rubber 33 between both ends of the wavy cord protection layer 28 in the longitudinal direction, as shown in FIG. 1A, the wavy cord 30 occupies the joining surface T of the wavy cord protection layer 28 butts. Even if the area of the surface becomes extremely large, the entire bonding surface T is bonded by the rubber 33 and the rubber 33, whereby the bonding force of the bonding surface T can be prevented from being lowered, and the wavy cord protective layer 28 can be prevented. It is possible to prevent separation of the bonding surfaces at both ends in the longitudinal direction.

The rubber 33 disposed between the longitudinal ends of the wavy cord protective layer 28 need not be the coating rubber 32 of the wavy cord 30.
Other rubbers capable of adhering to the coating rubber 32 may be used as long as the both ends in the longitudinal direction of 8 are bonded to each other.

If the wavy cord 30 of the wavy cord protective layer 28 is made of organic fiber such as Kevlar, nylon, polyester, etc., the wavy cord 30 has a larger diameter than the metal fiber, and therefore the wavy cord 30 is wavy. Code protection layer 2
The adhesion surface of the coating rubbers between both ends in the longitudinal direction of 8 becomes smaller. Therefore, it is essential to prevent the rubber 33 from peeling off the joint surface. (Test Example 1) A radial tire for aircraft 10 shown in FIGS. 1 (A) and 1 (B), which includes the corrugated cord protection layer 28 of the present embodiment, and FIGS. 7 (A) and 7 (B). And a radial aircraft tire provided with the corrugated cord protective layer 70 of the conventional example shown in Fig. 1 were prototyped according to the specifications of Table 1, and the radial tire for aircraft was run at a speed of 40 miles / hour and a load of 250.
A drum endurance test was repeated by repeating this for 1 cycle consisting of running for 8 minutes at 00 kg and an internal pressure of 15.6 kg / cm ² and stopping for 37 minutes. The results are shown in Table 1.

[0031]

[Table 1]

Aircraft tires have a speed of 40 miles /
In addition to running at a relatively low time, high-speed takeoff and landing is also performed. However, in consideration of this condition, in conventional tires where bond surface peeling occurs even under the above conditions, peeling occurs before 400 times in the tread groove bottom. It is expected that the tread will come off and the tread will peel off.

Therefore, it has been clarified that the above-described aircraft radial tire of the present invention is particularly excellent.

In this embodiment, the wavy cord having a waveform is used, but instead of this, a wavy cord having another shape such as a zigzag shape may be used.

[0035]

Since the radial tire for aircraft of the present invention has the above-mentioned structure, it has an excellent effect of preventing separation of the bonding surfaces at both longitudinal ends of the wavy cord protective layer.

[Brief description of drawings]

FIG. 1 (A) is an enlarged schematic plan view of an example of a wavy cord of a radial tire for an aircraft to which the present invention is applied, as seen from the outside in the tire radial direction, and FIG. 1 (B) is B- of FIG. B
It is a line sectional view.

FIG. 2 is a cross-sectional view in which an embodiment of an aircraft radial tire to which the present invention is applied is cut along the tire width direction and hatching is omitted.

FIG. 3 is a schematic plan view of the wavy cord protection layer of the present embodiment as seen from the outside in the tire radial direction.

FIG. 4 is a cross-sectional view taken along the tire width direction showing the hold belt of the present embodiment.

FIG. 5 is a plan view showing a hold belt of this embodiment.

FIG. 6 is a graph showing the relationship between the rubber gauge between the two ends in the longitudinal direction of the corrugated cord protective layer and the principal strain when the tire is used and filled with an internal pressure in this example.

FIG. 7A is an enlarged schematic plan view of a conventional wavy cord as seen from the outside in the tire radial direction, and FIG. 7B is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 10 Pneumatic radial tires for motorcycles 11 Carcass 12 Carcass 18 Tread 20 Belt layer 28 Wavy cord protective layer 30 Wavy cord 32 Coating rubber 33 Rubber

Claims (2)

[Claims] 1. A toroidal carcass comprising plies composed of cords arranged in parallel with each other, at least one ply having a turn-back portion that is wound around a pair of bead cores from the inner side to the outer side in the tire axial direction, and the carcass and the tire. A belt composed of a plurality of plies arranged between the tread and the tread, and between the belt and the tread, a plurality of wavy cords centered on the amplitude are arranged along the tire circumferential direction by a coating rubber. It has a wavy cord protective layer coated
In an aircraft radial tire in which both longitudinal ends of this protective layer are butted to each other, an aircraft radial tire characterized in that substantially the same rubber as the coating rubber is arranged between both longitudinal ends of the wavy cord protective layer. tire. 2. The radial tire for aircraft according to claim 1, wherein the wavy cord is made of organic fiber.