JPH0316808A - Pneumatic radial tire - Google Patents

Abstract

PURPOSE:To improve separatability of tread rubber, in a tire for a jet passenger airplane or the like, by setting the distance between the protective layer provided to the tread part and the belt at both ends in the tire width direction so as to be greater than that at the central part in the tire width direction. CONSTITUTION:The width of a protective layer 28 between both ends 28A in the tire width direction is made narrower than that of a cross belt 24 between both ends 24A in the tire width direction, and also the distance between the corrugated cord 30 of the protective layer 28 at both ends in the tire width direction and the cord of the cross belt 24 is set to be greater than that between both cords at the central part in the tire width direction, and further the distance at both ends is made greater than 1.5mm, while the distance at the central part is made less than 3.0mm. Furthermore, a cushion layer whose 100% extension modulus value is less than 70kg/cm<2> is interposed between the belt 24 and the protective layer 28. By this constitution, thickness deficiency and weight increase of tread rubber can be prevented, and separatability of tread rubber can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pneumatic radial tire for use in aircraft such as jet airliners.

[Conventional technology]

In recent years, pneumatic radial tires have come to be used on aircraft such as jetliners. Since this pneumatic radial tire is used with high internal pressure, the pressure on the ground contact surface is high. Therefore, when taking off and landing at high speed or driving through an airport, the tread rubber may be damaged by protrusions on the road surface. In particular, if this damage is large, the belt disposed inside the tread rubber in the radial direction of the tire will also be damaged, making it difficult to rehabilitate the tread rubber by replacing it.

To improve this, a pneumatic radial tire is constructed using a protective layer consisting of a wavy cord made of steel wire covered with a coating rubber, or a belt made of a straight cord made of organic fibers inclined with respect to the circumferential direction of the tire covered with a coating rubber. A pneumatic radial tire is known in which a protective layer with intersecting cords is placed between the tread rubber and the belt (Japanese Patent Application Laid-Open No. 5-7-2
0 1704).

In addition, when retreading this pneumatic radial tire, that is, when peeling off the worn tread rubber and reapplying the tread rubber, in order to improve the workability of peeling off the tread rubber, use a peeling means such as a knife on the side of the tire. The tread rubber is then peeled off from the tire body together with the protective layer by inserting the rubber between the belt and the protective layer and peeling the protective layer from the belt.

However, in this pneumatic radial tire, as shown in FIG. 9, there is almost no gap between the belt 52 and the protective layer 54 in the tire radial direction (vertical direction in FIG. 9). For this reason, when the protective layer 54 is peeled off from the belt 52, there is a risk that the belt 52 will be damaged by the knife and the durability of the pneumatic radial ear 50 will be reduced.

On the other hand, as shown in FIG. 10, the belt 56 and the protective layer 5
By inserting a cushion rubber layer 60 between the belt 56 and the protective layer 58, the pneumatic radial tire 62 improves the peeling efficiency of the protective layer 58 by widening the gap C in the tire radial direction between the belt 56 and the protective layer 58. It has been proposed (Japanese Patent Application No. 61307695).

However, this pneumatic radial tire 62 has problems in that increasing the thickness of the cushion rubber layer 60 causes the thickness of the tread rubber 64 to become insufficient and the weight of the tire to increase. Also, due to molding and vulcanization, the thickness of the cushion rubber layer 60 at both ends 60A in the tire width direction, that is, the thickness of the belt 56 at both ends 5.6A in the tire width direction.
The distance C between both end portions 58A in the tire width direction of the belt 56 and the protective layer 58 is smaller than the distance D between the tire width direction center portion 56B of the belt 56 and the tire width direction center portion 58B of the protective layer 58, and the tread rubber peeling workability is improved. There were cases where the improvement was not sufficient.

[Problem to be solved by the invention]

In consideration of the above-mentioned facts, the present invention aims to provide a pneumatic radial tire that can improve the workability of peeling the tread rubber without causing the tread rubber to become insufficiently thick or the tire weight to increase.

[Means and effects for solving the problem] The present invention provides a carcass in which cords are arranged in a radial direction, a tread rubber in which a belt for protecting the outermost part of the carcass in the tire radial direction is located at the outermost part in the tire radial direction, and the carcass. A pneumatic radial tire having one or more protective layers disposed between the belt and the tread rubber, wherein the cords of the protective layer and the cords of the belt at both ends in the width direction of the tire are arranged between the belt and the tread rubber. It is characterized in that the interval is wider than the interval at the center portion in the width direction of the tire.

As a result, when the protective layer is peeled off from the belt, a knife serving as a peeling means can be easily inserted between the protective layer and the belt, and the peeling workability is improved. Additionally, in general, the tread rubber of aircraft tires undergoes the most wear when landing at high speed, and at that time, the tread wear is greater near the center in the width direction of the tire, where it first begins to touch the ground, than on both shoulders. The thickness of the tread determines the lifespan of the tread, but since the gap between the protective layer and the belt increases only at both ends in the width direction of the tire, the tread rubber thickness may be insufficient across the width of the tire, or the thickness of the tread rubber may be insufficient in the center of the tread. The weight of the tire does not increase due to the thickness of the tire.

In addition, in order to reduce shear strain between the belt and the protective layer and improve the durability of the protective layer, a rubber material with a 100% extension modulus of 70 kg/cut or less is used between the belt and the protective layer. It is preferable to provide a cushion rubber layer.

Further, when peeling off the protective layer, it is preferable that the distance between the cord of the protective layer and the cord of the belt at both ends in the width direction of the tire is 1.5 mm or more so that a knife can be easily inserted as a peeling means.

Further, in order to ensure the thickness of the tread rubber, the distance between the cords of the protective layer and the cords of the belt at the center in the tire width direction is preferably 3.0 mm or less.

[Embodiments of the invention]

A first embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

As shown in FIG. 1, the carcass 11, 12 of the pneumatic radial tire 10 has Kerr force splies in which Kerr force sply cords are arranged radially around the rotational axis of the tire. Both ends of these car forceps 11 and 12 in the tire width direction extend from the inner side in the tire width direction (right side in Figure 1) to the outer side in the tire width direction, respectively, around a bead core 14 arranged in a ring shape on the inner periphery in the tire radial direction. (left side of Figure 1), respectively, 81IA, 1
It is said to be 2A.

The outside of this carcass 12 in the tire radial direction (upper side in Figure 1)
Carcass 15, 16 are arranged, and both ends of these carcass 15, 16 in the tire width direction extend around the bead core 14 from the outside in the tire width direction to the tire radial inside (lower side in Figure 1). They are folded back towards the end, forming folded parts 15A and 16A, respectively.

The outside of this carcass 16 in the tire radial direction (upper side in Figure 1)
A cross belt 18 as part of the belt is arranged along the carcass 16.

As shown in FIG. 2, cord 1 of this cross belt 18
9 is inclined at 18 degrees with respect to the circumferential direction of the tire (direction of arrow F), and is adapted to reinforce the tread rubber 27 disposed at the outermost position in the tire radial direction of the pneumatic radial tire 10. .

A circumferential belt 20 as a part of the belt is disposed outside the cross belt 18 in the tire radial direction (upper side in FIG. 1), and both ends 2OA of the circumferential belt 20 in the tire width direction are connected to the cross belt 18. Both ends in the tire width direction 18A
The inner side in the tire width direction (i.e., narrower width) than the tire width direction.

As shown in FIG. 2, the cord 21 of the circumferential belt 20
is along the circumferential direction of the tire and is designed to prevent standing waves of the pneumatic radial tire 10.

Cross belts 22 and 24 as part of the belt are located on the outside of the circumferential direction bell}20 in the tire radial direction (upper side in FIG. 1).
are arranged respectively, and these intersecting belts 22,
Both end portions 22A and 24A in the tire width direction of 24 are located on the inner side in the tire width direction than the circumferential belt 20 and on the inner side in the tire width direction than the crossing belt 22 (that is, narrow width).

As shown in FIG. 2, the cords 23 and 25 of the cross belts 22 and 24 are inclined at 22 degrees in different directions with respect to the circumferential direction of the tire, and cross each other. The tread rubber 27 of the radial tire is reinforced.

A protective layer 28 is disposed between the cross belt 24 and the tread rubber 27, and both ends 28A of the protective layer 28 in the tire width direction are wider in the tire width direction than both ends 24A of the cross belt 24 in the tire width direction. It is said to be inside (i.e. narrow).

This protective layer 28 has a configuration in which a wavy cord 30 is covered with a coating rubber 32, and the amplitude center line of this wavy cord 30 is along the tire circumferential direction.

Further, the distance between the protective layer 28 and the cross belt 24 increases from the central portion 28B in the tire width direction toward both end portions 28A in the tire width direction. That is, as shown in Figure 3,
The distance B between the wavy cord 30 of the protective layer 28 and the cord 25 of the crossing belt 24 at both ends in the tire width direction is the distance between the wavy cord 30 of the protective layer 28 and the crossing belt at the center part in the tire width direction shown in FIG. It is wider than the distance A between the code 24 and the code 25.

Therefore, when inserting a knife serving as a peeling means from the outside in the tire width direction between the wavy cords 30 of the protective layer 28 and the cords 25 of the cross belt 24, the knife can be easily inserted and the peeling work of the protective layer 28 can be improved. will improve.

Furthermore, since the distance between the wavy cords 30 of the protective layer 28 and the cords 25 of the cross belt 24 is narrow at the center in the width direction of the tire, the tread rubber 27 does not become insufficiently thick and the tire weight does not increase.

Next, a second embodiment of the present invention will be described with reference to FIG.

Note that the same members as those in the first embodiment are given the same reference numerals and the description thereof will be omitted.

As shown in FIG. 5, in the pneumatic radial tire 36 of the second embodiment, the wavy cords 30 of the protective layer 28 and the cords 25 of the cross belt 24 are located at the center in the width direction of the tire.
The distance A between the wavy cords 30 of the protective layer 28 is constant, and the wavy cords 30 of the protective layer 28
The distance B between the cord 25 of the cross belt 24 and the cord 25 of the cross belt 24 is increased.

In this case as well, the same effects as in the first embodiment can be obtained.

Next, a third embodiment of the present invention will be described with reference to FIG.

Note that the same members as those in the first embodiment are given the same reference numerals and the description thereof will be omitted.

As shown in FIG. 6, in the pneumatic radial tire 38 of the third embodiment, the wavy cords 30 of the protective layer 28 and the cords 25 of the cross belt 24 are located at the center in the width direction of the tire.
The distance A between them is approximately the thickness of the protective layer 28 and the coating rubber of the cord 25.

In this case, although the peeling workability of the protective layer 28 is slightly lower than in the first and second embodiments, substantially the same effects as in the first and second embodiments can be obtained.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. 7 and 8.

Note that the same members as those in the first embodiment are given the same reference numerals and the description thereof will be omitted.

As shown in FIG. 7, in the pneumatic radial tire 40 of the fourth embodiment, the protective layer 42 has a straight cord 44 made of organic fibers such as nylon in the tire circumferential direction F, as shown in FIG. Table 1 shows the results of comparing the peeling workability of the protective layer when the tread rubbers are arranged at an angle of 11 12 60 degrees and covered with coating rubber 46 to rehabilitate each of the tread rubbers shown in Table 1.

13 From the results of this experiment, it has become clear that the aircraft radial tire of the present invention described above is particularly excellent.

〔Effect of the invention〕

Since the present invention has the above structure, it has an excellent effect of improving the workability of peeling off the tread rubber without causing the tread rubber to become insufficient in thickness or increasing the weight of the tire.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a pneumatic radial tire according to a first embodiment of the present invention, cut along the tire width direction and partially omitted with hatching, and FIG. 2 is a tire showing the protective layer and belt of the first embodiment. 3 is an enlarged sectional view showing both ends of the protective layer and belt in the radial direction of the tire shown in FIG. 1; FIG. 4 is a schematic plan view of the protective layer and belt shown in FIG. 1 in the radial direction of the tire FIG. 5 is an enlarged cross-sectional view showing the central portion of the pneumatic radial tire according to the second embodiment of the present invention; FIG. The figure is a cross-sectional view of a pneumatic radial tire according to a third embodiment of the present invention, taken along the width direction of the tire, with some hatching omitted. FIG. 8 is a cross-sectional view of the tire radial outer part of the pneumatic radial tire cut along the tire width direction, with some hatching omitted; FIG. 8 is a schematic plan view seen from the tire radial outer side showing the protective layer in FIG. 7; , No. 9
The figure is a cross-sectional view of a pneumatic radial tire according to the prior art, with the outside part of the tire radially cut along the width direction of the tire, with some hatching omitted. FIG. 2 is a cross-sectional view of the outside portion taken along the width direction of the tire, with hatching partially omitted. 10, 36, 38, 40... Pneumatic radial tire, 11, 12, l5, 16... Carcass, 24... Cross belt, 25... Cord, 27... Tread rubber, 28, 42 ...Protective layer, 15 16 30... Wavy cord, 44... Cord.

Claims (4)

[Claims] (1) A carcass in which cords are arranged in a radial direction and a belt that protects the outermost part of the carcass in the radial direction of the tire are disposed between the tread rubber located at the outermost part in the radial direction of the tire and the carcass, and the belt and the tread rubber A pneumatic radial tire with one or more protective layers provided between the cords of the protective layer and the belt at both ends in the width direction of the tire, wherein the distance between the cord of the protective layer and the cord of the belt is wider than the distance at the center of the tire width direction. A pneumatic radial tire characterized by: (2) Claim (1) characterized in that a cushion rubber layer made of rubber having a 100% elongation modulus value of 70 kg/cm^2 or less is provided between the belt and the protective layer.
Pneumatic radial tires listed. (3) The pneumatic radial tire according to claim (1), wherein a distance between the cord of the protective layer and the cord of the belt at both ends in the tire width direction is 1.5 mm or more. (4) The pneumatic radial tire according to claim (1), wherein a distance between the cords of the protective layer and the cords of the belt at the center in the tire width direction is 3.0 mm or less.