JP3149260B2 - Aircraft radial tires - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

[0003] As a radial tire for an aircraft to improve this, as shown in FIGS. 7A and 7B, a plurality of wavy cords 72 having amplitude center lines W arranged along the tire circumferential direction are used. There is known an aircraft radial tire in which a wavy cord protective layer 70 covered with a coating rubber 74 is disposed between a tread portion and a belt (Japanese Patent Laid-Open No. Sho 5).
7-201704).

The corrugated cord protection layer 70 is joined at both ends in the longitudinal direction by abutting each other. Accordingly, in this aircraft radial tire, the thickness of the connecting surfaces at both ends in the longitudinal direction of the corrugated cord protection layer 70 becomes uneven, so that the tire vibrates in the tire radial direction during traveling. In order to reduce this, the coupling surface T is inclined with respect to the circumferential direction of the tire.

[0005]

However, the coating rubbers are adhered to each other at the joining surfaces at both ends in the longitudinal direction of the corrugated cord protective layer, but the mating surfaces of the corrugated cords or the butting of the corrugated cords and the coating rubber. The surfaces do not adhere to each other. For this reason, when the cross-sections at both ends in the longitudinal direction of the wavy cord do not coincide with each other at the bonding surfaces at both ends in the longitudinal direction of the corrugated cord protection layer, portions where the bonding surfaces do not adhere may continue. For this reason, there is a possibility that the bonding strength of the bonding surface is reduced and the bonding surface is separated.

The present invention has been made in view of the above circumstances, and has as its object to provide a radial tire for an aircraft which can prevent peeling of the bonding surfaces at both ends in the longitudinal direction of the corrugated cord protective layer.

[0007]

A radial tire for an aircraft according to the first aspect 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 the inside in the tire axial direction. A toroidal carcass having a folded portion wound outward and a belt composed of a plurality of plies arranged between the carcass and the tread of the tire, and an amplitude center line is provided between the belt and the tread. A radial tire for aircraft, comprising a wavy cord protection layer in which a plurality of wavy cords arranged along the tire circumferential direction are covered with a coating rubber, and both ends in the longitudinal direction of the protection layer are joined by butt. When the both ends in the longitudinal direction of the protective layer are bonded to each other when interposed ,
Cover the radially inner and outer parts of the tire at both ends.
Starts selling rubber is characterized in that the said coating rubber substantially the same rubber.

[0008] A radial tire for an aircraft according to a second aspect of the present invention is the radial tire for an aircraft according to the first aspect, wherein the wavy cord is made of organic fibers.

[0009]

In the radial tire for an aircraft according to the first aspect of the present invention, when the longitudinal ends of the corrugated cord protective layer are joined to each other, the wavy cord protective layer is interposed between the ends and is provided near the both ends.
The rubber covering the inside and outside of the tire in the radial direction is substantially the same rubber as the coating rubber, so that the mating surfaces of the corrugated cords or the mating surfaces of the corrugated cords do not come into contact with the coating rubber, and the corrugated cord protection layer At both ends in the longitudinal direction are rubber-to-rubber bonds. Accordingly, even when the cross-sections at both ends in the longitudinal direction of the wavy cord do not coincide with each other at the joining surfaces at both ends in the longitudinal direction of the corrugated cord protective layer, the entire coupling surface is securely adhered by rubber to rubber. For this reason, the coupling force of the coupling surface does not decrease, and separation of the coupling surfaces at both ends in the longitudinal direction of the corrugated cord protective layer can be prevented.

The rubber disposed between both ends in the longitudinal direction of the corrugated cord protective layer may not be the coating rubber of the corrugated cord. If possible, another rubber that can be bonded to the coating rubber may be used.

The radial tire for an aircraft according to the second aspect of the present invention is the radial tire for an aircraft according to the first aspect, wherein the cord of the corrugated cord protective layer is Kevlar (trade name: manufactured by Du Pont), nylon, Since it is made of an organic fiber such as polyester, the diameter of the corrugated cord is larger than that of the metal fiber. This is because it is necessary to increase the cross-sectional area of the organic fiber cord as compared with the metal fiber cord in order to make the breaking strength of the cord the same. In this case, the bonding surface between the coating rubbers between both ends in the longitudinal direction of the corrugated cord protective layer becomes small.

Therefore, when the both ends in the longitudinal direction of the corrugated cord protective layer are connected to each other, they are interposed between both ends and
Inside and outside of tire radial direction near both ends
The rubber covering the rubber is substantially the same as the coating rubber of the corrugated cord, so that the entire surface at both ends in the longitudinal direction of the corrugated cord protection layer can be securely adhered with the rubber and rubber regardless of the cross-sectional area of the corrugated cord. . For this reason, even if the corrugated cord is an organic fiber, the coupling strength of the coupling surface does not decrease, and peeling of the coupling surfaces at both ends in the longitudinal direction of the corrugated cord protective layer can be prevented.

[0013]

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

As shown in FIG. 2, the carcasses 11, 12 of the aircraft radial tire 10 (tire size 46 × 17R20) are made of carcass plies in which carcass ply cords are radially arranged around the rotation axis of the tire. Both end portions in the tire width direction of these carcass 11 and 12 are folded from the inside to the outside in the tire width direction around a ring-shaped bead core 14 disposed on the radially inner portion in the tire radial direction of the aircraft radial tire 10. Are turned back portions 11A and 12A, respectively.

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

Carcass 15, 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 in the tire width direction of these carcass 15, 16 are respectively arranged around the bead core 14. It is folded from the outer side in the tire width direction toward the inner side in the tire radial direction (the lower side in FIG. 2), and is formed as folded portions 15A and 16A, respectively.

On the outer side of the carcass 16 in the tire radial direction (upper side in FIG. 2), an intersecting belt 18 is arranged along the carcass 16, and the top arranged at the outermost position in the tire radial direction of the aircraft radial tire 10 is arranged. The rubber 27 is reinforced.

A circumferential belt 20 is disposed radially outward (upper side in FIG. 2) of the cross belt 18 in the tire width direction.
Are located outside (ie, wider) in the tire width direction than both end portions 18A of the cross belt 18 in the tire width direction.

As shown in FIG. 3, the cord 31 of the circumferential belt 20 extends along the circumferential direction of the tire (the direction of arrow S) to prevent a standing wave of the radial tire 10 for an aircraft.

Cross belts 21, 22, and 24 are arranged on the outer side of the circumferential belt 20 in the tire radial direction (upper side in FIG. 2).
2, 24, both ends 21A, 22A, 24A in the tire width direction
Are arranged inward in the tire width direction from the circumferential array belt 20, and as the cross belt is located radially outward, both end portions in the tire width direction are located inward (ie, narrower) 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 with each other so as to reinforce the top rubber 27 of the radial tire 10 for aircraft. Has become.

Further, as shown in FIG.
Reference numerals 8 and 21 each represent a four-layer hold belt. That is, the first layer A, the second layer A
Layer B and third layer C are provided, and both ends in the tire width direction of the first layer A wrap around the second layer B and the third layer C to form both ends D in the tire width direction of the fourth layer. Further, the central portion E in the tire width direction of the fourth layer is formed 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 (the direction of arrow S) is 24 ° to the left in the first layer A and 22 ° to the right in the second layer B. °, 22 ° to the left in the third layer C, 24 ° to the right at both ends D in the tire width direction of the fourth layer, and 22 ° to the right in the center E in the tire width direction of the fourth layer. The circumferential direction of the tire of the cord 34 of the cross belt 21 (arrow S
Is 20 ° to the left in the first layer A, 18 ° to the right in the second layer B, 18 ° to the left in the third layer C, and 18 ° to the left in the tire width direction both ends D of the fourth layer, respectively. To 1
8 °, 20 ° to the right at the center E of the fourth layer in the tire width direction
It has been.

As shown in FIG. 2, the cross belt 24 is
An outermost layer belt in the tire radial direction is provided, and a wavy cord protection layer 28 is disposed between the cross belt 24 and the top rubber 27. Both end portions 28A of the wavy cord protection layer 28 in the tire width direction are The inner side in the tire width direction (i.e., narrower width) than both end portions 24A of the cross belt 24 in the tire width direction.

As shown in FIG. 1 (A), 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 is in the tire circumferential direction. (Direction of arrow S in FIG. 1A)
Are arranged along. The connecting surfaces T at both ends in the longitudinal direction of the corrugated cord protective layer 28 are inclined at a predetermined angle α with respect to the amplitude center line W (the tire circumferential direction). Length (K in Fig. 3)
Becomes longer, and the connecting surface T does not concentrate in a narrow range in the tire circumferential direction, so that the aircraft radial tire 10 does not vibrate largely in the tire radial direction on the connecting surface T during traveling.

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

As shown in FIG. 6, the main strain of the joint surface T when the internal pressure of the tire is filled is that the thickness 2G of the rubber 33 interposed between both ends in the longitudinal direction of the corrugated cord protection layer 28 increases. The thickness G of the rubber 33 only needs to be 0.1 mm or more, since the value gradually decreases as 0.005 mm is set to 100, and when the thickness is 0.1 mm, the value decreases to 50% at 0.1 mm.

The rubber 33 is interposed between both ends in the longitudinal direction of the corrugated cord protection layer 28 so that the corrugated cords 30 occupying the joint surface T of the corrugated cord protection layer 28 as shown in FIG. Even when the area of the surface becomes extremely large, the entire surface of the coupling surface T is bonded to the rubber 33 and the rubber 33 can be prevented from lowering the coupling force of the coupling surface T. Can be prevented from peeling off at the bonding surfaces at both ends in the longitudinal direction.

The rubber 33 disposed between both ends in the longitudinal direction of the corrugated cord protection layer 28 does not have to be the coating rubber 32 of the corrugated cord 30.
As long as the connection at both ends in the longitudinal direction of 8 is a connection between rubber and rubber, another rubber that can be bonded to the coating rubber 32 may be used.

When the corrugated cord 30 of the corrugated cord protection layer 28 is made of an organic fiber such as Kevlar, nylon or polyester, the cord diameter of the corrugated cord 30 is larger than that of the metal fiber. Code protection layer 2
8, the bonding surface between the coating rubbers between both ends in the longitudinal direction becomes smaller. Therefore, it is essential to prevent the rubber 33 from peeling off the bonding surface. (Test Example 1) An aircraft radial tire 10 provided with the corrugated cord protection layer 28 of the present embodiment shown in FIGS. 1A and 1B, and FIGS. 7A and 7B. And prototype aircraft radial tires provided with the wavy cord protection layer 70 according to the conventional example shown in Table 1 were prototyped according to the specifications shown in Table 1, and these aircraft radial tires were manufactured at a speed of 40 miles / hour and a load of 250.
The running was repeated for 8 minutes at an internal pressure of 15.6 kg / cm ² and a stop of 37 minutes at a pressure of 15.6 kg / cm ² , and the cycle was repeated. The drum durability test was repeated to examine the peeling of the bonding surfaces at both ends in the longitudinal direction of the corrugated cord protection layer. 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 speed for a long time, high-speed running for take-off and landing is also performed. In consideration of this condition, in the conventional tire where the joint surface peels even under the above conditions, the peeling occurs at the bottom of the tread groove before 400 times. It is expected that the tread will spread and the tread will peel off.

Accordingly, it has been clarified that the above-described radial tire for aircraft according to the present invention is particularly excellent.

In this embodiment, a wave-like code having a waveform is used. Alternatively, a wave-like code having another shape such as a zigzag shape may be used.

[0035]

The radial tire for an aircraft according to the present invention has the above-mentioned structure, and therefore has an excellent effect that the connecting surfaces at both ends in the longitudinal direction of the corrugated cord protective layer can be prevented.

[Brief description of the drawings]

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

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

FIG. 3 is a schematic plan view of the corrugated cord protective layer of the present embodiment as viewed from the outside in the tire radial direction.

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

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

FIG. 6 is a graph showing the relationship between the rubber gauge between both ends in the longitudinal direction of the corrugated cord protective layer of the present embodiment and the main strain at the time of filling the tire under internal pressure.

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

[Explanation of symbols]

 Reference Signs List 10 Pneumatic radial tire for motorcycle 11 Carcass 12 Carcass 18 Tread 20 Belt layer 28 Corrugated cord protection layer 30 Corrugated cord 32 Coating rubber 33 Rubber

Claims (2)

(57) [Claims] 1. A toroidal carcass having a folded portion wound around a pair of bead cores from the inside to the outside in the tire axial direction, comprising at least one ply consisting of cords arranged in parallel with each other, and the carcass and the tire. A belt comprising a plurality of plies disposed between the tread and the tread, between the belt and the tread, a plurality of corrugated cords whose amplitude center lines are arranged along the tire circumferential direction by coating rubber. Having a coated wavy cord protective layer,
In the radial tire for an aircraft in which both ends in the longitudinal direction of this protective layer are joined by butt, when the both ends in the longitudinal direction of the wavy cord protective layer are joined to each other, they are interposed between the both ends, and
A radial tire for aircraft, wherein the rubber covering the radially inner and outer portions in the tire radial direction is substantially the same as the coating rubber. 2. The radial tire for an aircraft according to claim 1, wherein the corrugated cord is made of an organic fiber.