JPH04103414A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To restrain the deformation of a bead bundle near to a bead toe and prevent 'wide wire', by making the total strength of the bead bundle near to the bead toe larger than those of bead bundles on a bead heel side. CONSTITUTION:A tire 1 is equipped with a pair of bead portions 2, a pair of side wall portions 3 extending toward an approximate radial outside from bead portions 2 and an approximately cylindrical tread portion 4 putting portion 3 radial fellow outer ends in a row, and a bead portion 1 is seated at a rim 5 bead seat portion 7. And a plurality of bead bundles 6 are embedded in a bead portion 2. In this instance, the total strength of an inner side bead bundle 6a is made larger than those of a middle and an outer side bead bundles 6b, 6c by making the row number of the step number of filaments constituting the bundle 6a larger than the row number of the step number of filaments constituting bundles arranged more on a bead heel side 2 than the bundle 6a, that is, the middle bead bundle 6b, the outer side bead bundle 6c.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a pneumatic tire in which two or more bead bundles are embedded in each bead portion.

[Higashiho and I Conventionally, pneumatic tires for heavy loads installed on aircraft, etc., have a pair of bead portions in which two or more bead bundles having the same total strength are buried, and a short distance from these bead portions. A vehicle that includes a pair of sidewall portions extending radially outward and a tread portion connecting these sidewall portions is known.

However, if such a pneumatic tire is attached to an aircraft and it travels,
Due to the enormous load, the sidewall on the ground contact side of the pneumatic tire collapses significantly outward in the axial direction starting from the rim flange, and a large tensile force is applied to the bead bundle embedded in the bead, causing it to expand in the circumferential direction. In particular, the largest tensile force is applied to the bead bundle located closest to the bead tow to cause it to expand largely in the circumferential direction.

Moreover, at this time, the temperature of the bead portion increases due to heat generation due to tire rotation, braking, etc., and the adhesive strength or rubber modulus between the bead rubber and the bead bundle decreases. The bead bundle placed in the bead may be the first to separate from the bead rubber. When the bead bundle peels off from the bead rubber in this way, the filaments that make up the bead bundle are subjected to compression bending and break in the middle, causing the problem that they may fly out from the outer surface of the pneumatic tire (creating wild wires). be.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire that suppresses deformation of a bead bundle disposed closest to a bead tow to prevent wild wire.

This purpose is to provide a pair of bead portions in which two or more bead bundles are embedded, a pair of sidewall portions extending approximately radially outward from these bead portions, and a In a pneumatic tire equipped with a tread section that connects the tread sections, the total strength of the bead bundle located closest to the bead toe is greater than the total strength of the bead bundles located closer to the bead heel than the bead bundle. This can be achieved by

Suppose that, for example, an aircraft equipped with the above-mentioned pneumatic tires is traveling on a road in January.

At this time, since a significant load is applied to the pneumatic tire from the aircraft, the sidewall portion on the grounding side collapses significantly outward in the axial direction starting from the rim flange portion, causing the bead bundle buried in the bead portion to collapse. A large tensile force acts, especially the largest tensile force acts on the bead bundle located closest to the bead. However, the total strength of the bead bundle placed closest to the bead toe is greater than the total strength of the bead bundles placed closer to the bead heel than the bead toe. Even when a large tensile force is applied, it does not elongate much in the circumferential direction and deformation is suppressed. Also, at this time,
The temperature of the bead increases due to heat generation due to tire rotation, braking, etc., and the adhesive strength or rubber modulus between the bead rubber and the bead bundle decreases. Since the elongation of the arranged bead bundles is suppressed, none of the bead bundles will peel off from the bead rubber, thereby preventing the filaments constituting the bead bundles from becoming wild wires.

Look up l Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, reference numeral 1 denotes a pneumatic tire to be mounted on an aircraft. , and a substantially cylindrical tread portion 4 that connects the outer ends of the sidewall portions 3 in the radial direction, and when the bead portion 1 is seated on the bead seat portion 7 of the rim 5, the tire 1 is attached to the rim. 5
will be installed on the Each of the bead portions 2 has two or more,
In this embodiment, three bead bundles 6 are buried, and each bead bundle 6 is constructed by arranging, for example, a plurality of rows of steel filaments and stacking them in a plurality of stages. Further, the tire 1 is reinforced with a toroidal-shaped laminate 12 extending from one bead part 2 to the other bead part 2, and this laminate 1
2 is composed of a plurality of layers, in this example, three carcass layers 13. Both ends of the carcass layer 13 in the width direction are folded back around the bead bundle 6 from the inside to the outside. Further, the carcass layer 13
is constructed by overlapping a plurality of carcass plies, and in this embodiment, all carcass layers 13 are constructed from four carcass plies, and an organic fiber cord, such as a nylon cord, is embedded in each carcass ply. . These cords are arranged to cross each other in adjacent carcass plies. A tread rubber 17 is arranged on the radially outer side of the laminate 12, and on the outer surface of the tread rubber 17, a plurality of rubber pieces extending substantially in the circumferential direction (substantially parallel to the tire equatorial plane J) are arranged. In this case, four main grooves 18 are formed.

Here, when an aircraft equipped with the above-mentioned tires l is run on a runway, the tires l receive a significant load from the aircraft, so that the sidewall portion 3 on the ground contact side
starts from the flange portion 8 of the rim 5 and falls significantly outward in the axial direction. As a result, a large tensile force acts on each bead bundle 6 buried in the bead portion 2, and each bead bundle 6
In particular, the largest tensile force acts on the inner bead bundle 6a located closest to the bead tow 2a, and the bead bundle 6a tends to elongate the most in the circumferential direction. However, in this example,
At least one of the number of rows or the number of stages of filaments constituting the inner bead bundle 6a is
a bead bundle arranged closer to the bead heel 2b than a;
Here, the number of rows and stages of filaments constituting the intermediate bead bundle 6b and the outer bead bundle 6c are set to be larger than the total strength of the inner bead bundle 6a.
b, the total strength is greater than 6C. Therefore, even if a large tensile force as described above is applied to the inner bead bundle 6a,
The inner bead bundle 6a does not expand much in the circumferential direction and deformation is suppressed. Note that, since the tensile force acting on the intermediate and outer bead bundles 6b and 6C is smaller than the tensile force acting on the inner bead bundle 6a, these intermediate and outer bead bundles 6b and 6c do not extend much in the circumferential direction. Furthermore, at this time, the temperature of the bead portion 2 increases due to the heat generated due to the rotation of the tire 1 and the braking, and the adhesive strength or rubber modulus between the bead rubber and the bead bundle 6 decreases. Since the elongation of the inner bead bundle 6a is suppressed, none of the bead bundles 6a, 6b, and 60 will peel off from the bead rubber, and as a result, the filament forming the bead bundle 6, especially the inner bead bundle 6a, will not peel off from the bead rubber. wild wires are prevented. If there is a difference in the number of carcass plies constituting each carcass layer 13, the total strength of the bead bundle 6 can be changed in proportion to the number of carcass plies wound up into the bead bundle 6. good. The total strength of the inner bead bundle 6a is determined by assuming that the number of carcass plies wound on the inner bead bundle 6a is A, and the bead bundle 6 closest to the bead heel 2b, in this embodiment, the outer bead bundle 6c. When the total strength of the carcass ply is 100 and the number of carcass plies wound on the bead bundle 6C is B, it is preferable that the number A is divided by the number B, which is only within the range of 105 to 120. .

The reason for this is that if the total strength of the inner bead bundle 6a is less than the above range, the expansion of the inner bead bundle 6a will be insufficiently suppressed and there is a risk of generating wild wires, whereas if it exceeds the above range, This is because the rigidity of the bead portion 2 increases, which deteriorates the heat generation property and increases the weight.

For example, inner, middle and outer bead bundles 6a, 6b, 6
When there are four carcass plies wound up in C, the total strength of the intermediate and outer bead bundles 6b and 6C is 100, and the total strength of the inner bead bundle 6a is 10.
It is preferable that the number is in the range of 5 to 120. Also, if the number of carcass plies wound on the middle and outer bead bundles 6b and 6c is four each, and the number of carcass plies wound on the inner bead bundle 6a is six, , the total strength of the outer bead bundle 6c and the intermediate bead bundle 6b is each 100,
The total strength of the inner bead bundle 6a is preferably in the range of 158 to 180.

Next, a test example will be explained. For this test,
A comparative tire in which four carcass plies were wound around each of the outer and middle bead bundles, and the total strength of these inner, outer and middle bead bundles was all set to the same index of 100; A test tire was prepared in which the carcass plies were wound up, the intermediate and outer bead bundles had the same total strength of 100, and the inner bead bundle had a total strength of 111. In addition, in this test, the total strength was 100 for a structure with 15 stages and 9 rows. Here, the size of these tires was 49X1730PR. Next, for each tire
When a load of 25,422 kg is applied, the internal pressure is adjusted so that the tire deflection is 50% of the section bite.
The drum was intermittently run straight for 650 km at 64 km/h, and the appearance of the bead portion at the end of the run was observed.

The results showed that in the comparison tire, one filament constituting the cord bundle protruded from the bead (one wild wire was generated), but in the test tire,
There was no filament protrusion.

In the above embodiment, three bead bundles 6 are buried in each bead portion 2, but in the present invention, two or four or more bead bundles are buried. Good too.

As described above, according to the present invention, the deformation of the bead bundle located closest to the bead tow is suppressed, and the generation of wild wires is prevented.

[Brief explanation of the drawing]

FIG. 1 is a meridian sectional view showing one embodiment of the present invention. 1... Pneumatic tire 2... Bead portion 2a...
・Bead toe 2b...Bead heel 3...Side wall part 4...Tread part 6...Bead bundle Patent applicant Brideston Co., Ltd. Agent Patent attorney Ta 1) Toshio

Claims (1)

[Claims] An air vehicle comprising: a pair of bead portions each having two or more bead bundles embedded therein; a pair of sidewall portions extending substantially radially outward from these bead portions; and a tread portion connecting these sidewall portions. 1. A pneumatic tire characterized in that the total strength of a bead bundle located closest to a bead toe is greater than the total strength of a bead bundle located closer to the bead heel than the bead bundle.