JPH0370603A - Pneumatic radial tire - Google Patents

Abstract

PURPOSE:To prevent a standing wave by providing a cross belt having coefficient of contraction in the direction of width of a tire due to valcanizing heat within a specific range and dimension in the direction of width of a tire after vulcanization narrower than a circumferential belt in the inside in the radial direction of the tire of the circumferential belt. CONSTITUTION:A cross belt 18 is provided in the outside of a radial direction of tire of a crown portion 16B in the carcass 16 of the tire 10. A cord 19 of the cross belt 18 is inclined relative to a circumferential direction C of the tire, thereby tread rubber being reinforced. A circumferential belt 20 is provided in the outside of the radial direction of the tire of the cross belt 18. At this time, a cord 21 of the circumferential belt 20 is disposed in the circumferential direction C of the tire. Both end portions 20A in the direction of width of the tire are disposed at the outside of both end portions 18A in the direction of width of the tire of the cross belt 18 and set so as to have larger width than those. Further, coefficient of contraction in the direction of width of the tire of the cross belt 18 due to vulcanizing heat is set to within a range of 5 to 15%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pneumatic radial tire, and particularly to a pneumatic radial tire used in an aircraft such as a jet airliner.

[Conventional technology]

In recent years, pneumatic radial tires have come to be used on aircraft such as jetliners. This pneumatic radial tire allows aircraft to take off and land at high speed.
Standing waves are likely to occur.

As a pneumatic radial tire that has improved this, as shown in FIG. 6, on the inside of the tread rubber 40 in the tire radial direction (lower side in FIG. 6), which is arranged at the outermost part in the tire radial direction,
A pneumatic radial tire 48 is known in which a circumferential heald 46 is arranged with a cross belt 42 interposed therebetween, and a cord 44 of the circumferential belt 46 runs along the tire circumferential direction.

However, in this pneumatic radial tire 48, when the circumferential belt 46 is arranged adjacent to the crown portion 50A located on the outside in the tire radial direction of the carcass 50, the rigidity of the circumferential belt 46 increases and the tire becomes stiffer. It becomes difficult to deform.

Therefore, the difference in diameter between the center portion of the tread rubber 40 in the width direction of the tire and both ends cannot be absorbed by deformation of the tire. Therefore,
During running, both ends of the tire in the width direction are dragged by the center in the tire width direction, and uneven wear occurs at both ends of the tread rubber 40 in the tire width direction.

For this reason, in this pneumatic radial tire 48, a cross belt 52 is disposed between the circumferential belt 46 and the carcass 50, and the diameter difference between the center and both ends of the tread rubber 40 in the width direction of the tire is compensated for by the deformation of the tire. I try to absorb it.

However, both ends 5 of the cross belt 52 in the tire width direction
2A has a lower rigidity in the tire circumferential direction than the center part in the tire width direction of the cross belt 52, and both ends 52 in the tire width direction
A standing wave is likely to occur.

[Problems solved by the invention]

The present invention has been made in consideration of the above facts, and an object of the present invention is to obtain a pneumatic radial tire that can prevent standing waves from occurring at both ends in the width direction of the tire.

[Means and actions to solve the problem]

The present invention provides a pneumatic radial tire that includes a toroidal carcass in which cords are arranged in a radial direction and whose ends are moored to a pair of bead cores, and a circumferential belt that reinforces the crown portion of the carcass located on the outside in the tire's radial direction. The circumferential belt is arranged in contact with the inner side of the tire in the radial direction and has a contraction rate of 5% or more in the tire width direction due to vulcanization heat.
5% or less, and the width of the tire after vulcanization is narrower than the circumferential belt.

In the conventional structure, the circumferential belt has the same width or a narrow width as the cross belt in the tire width direction, which causes staining waves to occur at both ends in the tire width direction.

The present invention is a pneumatic radial tire that aims to prevent the formation of standing waves at both ends in the width direction of the tire.

That is, a circumferential belt is placed on the outer side in the tire radial direction of the cross belt whose shrinkage rate in the tire width direction due to vulcanization heat is 5% or more and 15% or less, and the width in the tire width direction after vulcanization is narrower than the circumferential belt. By arranging the cross belts in contact with each other, this cross belt contracts inward in the tire width direction due to the heat of vulcanization during vulcanization, and becomes narrower than the circumferential belt. Therefore, in the product tire after vulcanization, both ends of the cross belt in the tire width direction are covered by the circumferential belt. Therefore, it is possible to prevent the formation of staining waves at both ends in the width direction of the tire.

Further, if the tensile elastic modulus of the cords of the circumferential belt and the cross belt differ significantly, the internal pressure safety factor will decrease. In other words, if the tensile modulus of the cord used in the circumferential belt is significantly higher than that of the cord used in the cross belt,
The tension generated in the cord due to internal pressure is higher in the circumferential belt and lower in the cross belt, causing the circumferential belt to break first. On the other hand, if the circumferential belt tends to stretch, the total strength of the belt decreases, and in order to obtain the necessary internal pressure stability, it becomes necessary to increase the total number of belts, leading to an increase in the weight of the tire. Therefore, it is desirable that the cords used for the circumferential belt and the cross belt be made of the same material and have similar tensile modulus.

Further, the width of the cross belt in the tire width direction of the completed tire after vulcanization is 65% or more of the width of the pneumatic radial tire.
% or less.

[Embodiments of the invention]

An 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 consists of carcass plies in which carcass ply cords are arranged radially around the rotation axis of the tire, and the tire width of these carcass 11.12 is Both end portions are folded back from the inner side in the tire width direction (right side in Figure 1) to the outer side (left side in Figure 1) around the bead core 14 arranged in a ring shape on the inner periphery of the tire in the radial direction. Sections 11A and !2A.

The outside of this carcass 12 in the tire radial direction (upper side in Figure 1)
A carcass 15, 16 is arranged in the tire, and both ends of the 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)
is the crown part 16B, and this crown part 1
A cross belt 18 is arranged along the carcass 16 on the outer side of the tire 6B in the radial direction.

As shown in FIG. 2, the cord 19 of the cross bell 18 is inclined at 22 degrees with respect to the circumferential direction of the tire (arrow C direction), and is located at the outermost part in the tire radial direction of the pneumatic radial tire 10. The tread rubber 28 is reinforced.

A circumferential belt 20 is disposed outside the cross belt 18 in the tire radial direction (upper side in FIG. 1). As shown in FIG. 2, the cord 21 of the circumferential belt 20 is
It extends along the circumferential direction of the tire, and both ends 2OA of the circumferential belt 20 in the tire width direction are located outside (that is, wider) in the tire width direction than both ends 18A of the cross belt 18 in the tire width direction. Further, both ends 2OA of the circumferential belt 20 in the tire width direction are curved inward in the tire radial direction, and cover both ends 18A of the cross belt 18 in the tire width direction.

Cross belts 22, 24, 26 are arranged on the outside of the circumferential belt 20 in the tire radial direction (upper side in FIG. 1), and both ends 22A, 124A, and 26A is located on the inner side in the tire width direction (that is, narrower) than the circumferential belt 20 and the cross belts 22 and 24, respectively.

As shown in FIG. 2, each cord 23, 25, 27 of the cross belt 22, 2426 is inclined at 22 degrees in a different direction with respect to the circumferential direction of the tire, and is designed to intersect with each other. , pneumatic radial tire 10
The tread rubber 28 is reinforced.

Next, a method for manufacturing the pneumatic radial tire 10 of this embodiment will be explained with reference to FIGS. 3 to 5.

As shown in FIG. 3, a circumferential belt having approximately the same width as the cross belt 18 is placed on the outside in the tire radial direction of the cross belt 18 whose contraction rate in the tire width direction due to vulcanization heat is 5% or more and 15% or less. Place 20. A cross belt 22.24.2 on the outside of the circumferential belt 20 in the tire radial direction has a shrinkage rate in the tire width direction due to vulcanization heat of 5% or more and 15% or less.
6 are placed in contact with each other.

As shown in FIG. 4, this pneumatic radial tire 1
0 is molded and vulcanized, each cross belt 18.22.24
．． 26 contract inward in the tire width direction (in the direction of the arrow in FIG. 4) due to the heat of vulcanization. On the other hand, the circumferential belt 20 has a cord 21 along the tire circumferential direction,
It does not shrink in the six directions of the arrow.

Therefore, as shown in FIG. 5, in the pneumatic radial tire 10 after vulcanization, both ends 2OA of the circumferential belt 20 in the tire width direction are on the outside in the tire width direction than both ends 18A of the cross belt 18 in the tire width direction. (that is, wide), and covers both ends 18A of the cross belt 18 in the tire width direction. In addition, before vulcanization, both ends 20A of the circumferential belt 20 in the tire width direction and both ends 18A of the cross belt 18 in the tire width direction
Since air does not enter between 30 and the tire width direction both ends 2OA of the circumferential belt 20 and the cross belt 18 after vulcanization,
No residual air is generated between the tire and both ends 18A in the width direction of the tire.

The wide circumferential belt obtained by this manufacturing method suppresses standing waves that occur in the tire during high-speed running.

(Experiment Example 1) The first example (first example) was prototyped with each specification shown in Table 1.
The results of measuring the standing wave generation speed and belt durability of the pneumatic radial tire 10 (tire size 46x17R20) shown in Fig. 6 and the conventional pneumatic radial tire 48 (comparative example) shown in Fig. Table 1 Table 1 *1: Certification test TS stipulated by the US Federal Aviation Administration (FAA)
The speed at which a standing wave occurs when performing a takeoff test with a normal load based on OC62C.

*2: A held failure that occurs in a tire after 50 takeoff tests under the same conditions as *1.

The results of this experiment have revealed that the pneumatic radial tire of the present invention described above is particularly excellent.

〔Effect of the invention〕

Since the present invention has the above configuration, it has an excellent effect of preventing the occurrence of standing waves at both ends in the width direction of the tire.

[Brief explanation of drawings]

Fig. 1 is a sectional view taken along the tire width direction showing the upper left part of a pneumatic radial tire according to an embodiment of the present invention, with hatching partially omitted, and Fig. 2 shows a circumferential belt of the present embodiment. FIG. 3 is a schematic plan view of the tire viewed from the outside in the radial direction of the tire; FIG. Figure 4 is a cross-sectional view of the upper left part of the tire during vulcanization, cut along the width direction of the tire, with some hunting omitted;
Fig. 5 is a cross-sectional view taken along the tire width direction showing the upper left part after vulcanization, with hatching partially omitted, and Fig. 6 is a cross-sectional view taken along the tire width direction showing the left upper part of a pneumatic radial tire of the prior art. FIG. 10 ・ ・ 11.1 16B ・ 18 ・ 20 ・ Pneumatic radial tire 1 . 15.16... Carcass, ・Crown part, Cross belt, Circumferential belt.

Claims (5)

[Claims] (1) A pneumatic radial tire with a toroidal carcass in which cords are arranged in a radial direction, both ends of which are moored to a pair of bead cores, and a circumferential belt that reinforces the crown portion of this carcass located on the outside in the tire's radial direction. The circumferential belt is placed in contact with the inside of the tire in the radial direction, and the shrinkage rate in the tire width direction due to vulcanization heat is 5% or more and 15%.
1. A pneumatic radial tire characterized by having a cross belt having a cross-belt having the following width and a tire width direction dimension after vulcanization that is narrower than the circumferential belt. (2) The pneumatic radial tire according to claim 1, wherein the contraction rate of the cord of the circumferential belt due to heat of vulcanization is 6% or less at a vulcanization temperature of 150° C. or less. (3) The pneumatic radial tire according to claim 1, wherein the cords of the circumferential belt are made of the same material as the cords of the crossing belt. (4) The width in the tire width direction of the circumferential belt of the completed tire after vulcanization is 1.0 times or more and 1.06 times or less the width of the cross belt in the tire width direction after vulcanization. The pneumatic radial tire according to claim (1). (5) The pneumatic radial according to claim (1), wherein the width of the cross belt in the tire width direction of the completed tire after vulcanization is 65% or more and 90% or less of the width of the pneumatic radial tire. tire.