JP2000094903A - Tubeless tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tubeless tire capable of maintaining durability and attaining lightening of weight. SOLUTION: A tubeless tire is provided with a carcass 6 extended between bead cores 5, 5, belt layer 7, and a bead apex rubber 8. The carcass 6 consists of a sheet of carcass ply 6A, to form a tire internal space surface (i) by a toroid-shaped main body part 6a. A folded end part 6be of a folded part 6b is positioned in a tire radial direction inner side from an outer end 8e of the bead apex rubber. In a topping rubber of a carcass ply 6A, only an inner side topping part serving as the tire internal space surface is formed by butyl rubber. An auxiliary cord ply 13 having an end part in a position with a 10 to 15 mm distance apart to a tire radial direction outer side from the outer end 8e of the bead apex rubber to extend to a tire radial direction inner side in an outer end part of at least the belt layer is provided in an outer side of the carcass 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubeless tire capable of achieving weight reduction while improving durability, steering stability, ride comfort and the like in a well-balanced manner.

[0002]

2. Description of the Related Art In recent years, with the recent strong demand for resource saving and low fuel consumption, further reduction in the weight of tubeless tires has been desired. In general tubeless tires, an inner liner made of butyl rubber, which has excellent air impermeability, is internally applied to the inner surface of the carcass facing the tire cavity in order to prevent leakage of the internal pressure air. Attempts have been made to reduce the tire weight by omitting the liner.

For example, JP-A-8-113007 discloses that
In the carcass ply, it has been proposed to form only the topping rubber on the inner side of the tire out of the topping rubber covering both sides of the carcass cord with butyl rubber. In such a tubeless tire, since the carcass ply also has the function of the inner liner, the conventional inner liner can be eliminated and the weight can be reduced.

[0004] However, butyl rubber has some difficulties in adhesiveness to other rubbers. For this reason, in a tire using butyl rubber as a topping rubber for a carcass ply, ply separation or the like is likely to occur at the folded end portion of the carcass ply where distortion during running is liable to concentrate, resulting in low durability.

[0005] Also, butyl rubber has low rebound resilience and is inferior in characteristics as a rubber elastic body, as compared with diene rubbers generally used as topping rubber. As a result, when this butyl-based rubber is used as a topping rubber, the elasticity and rigidity of the tire are impaired, and a new problem occurs in that the balance between steering stability and ride comfort is deteriorated, and actual vehicle performance is reduced. I do. If the number of carcass plies is increased or a diene rubber layer is added to maintain the actual vehicle performance, the weight cannot be reduced.

The present invention has been devised in view of the above-mentioned problems. Only the inner topping portion of the carcass ply is formed of butyl rubber, the position of the folded end is regulated, and the auxiliary cord is provided. It is an object of the present invention to provide a tubeless tire capable of achieving weight reduction while enhancing durability, steering stability, ride comfort, and the like in a well-balanced manner by appropriately arranging plies and the like.

[0007]

According to a first aspect of the present invention, there is provided a carcass extending between bead cores of a bead portion, and a belt disposed radially outside the carcass and inside a tread portion. A layer and a bead apex rubber made of hard rubber and extending radially outward from the outer surface of the bead core in the tire radial direction, wherein the carcass extends from the tread portion to the bead core of the bead portion via the sidewall portion. The carcass ply is composed of a ply body portion and a single carcass ply integrally formed with a ply folded portion that is continuous with the ply body portion and is folded around the bead core from the inside to the outside in the tire axial direction, and the carcass ply is a ply body portion. And the folded end of the ply folded portion is beaded The carcass ply is located on the inner side in the tire radial direction from the outer end of the pex rubber in the tire radial direction, and the carcass ply has a code array in which a plurality of carcass cords are arranged, and a topping rubber that covers both surfaces of the code array. Comprising, and said topping rubber,
Only the inner topping portion, which is provided in the area where the ply body is formed and forms the tire cavity surface, is covered with the rubber base material 10.
A butyl rubber containing 10 parts by weight or more of butyl rubber or a derivative thereof in 0 parts by weight is formed, and both sides of a code array in which cords are arranged outside the carcass are made of a non-butyl rubber topping rubber. Providing a coated auxiliary cord ply, and the auxiliary cord ply,
The end portion of the bead apex rubber has an end portion at a distance of 10 to 15 mm outward in the tire radial direction from the outer end of the bead apex rubber,
It is characterized in that it extends at least inward in the tire radial direction at the outer end of the belt layer.

According to a second aspect of the present invention, in the bead apex rubber, the outer end is located at a height of 0.15 to 0.55 times a tire sectional height H from a bead base line, and Distance h in the tire radial direction between the outer end of the apex rubber and the folded end of the carcass ply
The tubeless tire according to claim 1, wherein is not less than 5 mm.

According to a third aspect of the present invention, the auxiliary cord ply is formed of a single continuous ply extending continuously across the end portions. It is a tubeless tire.

According to a fourth aspect of the present invention, the auxiliary cord ply is formed of a pair of left and right interrupted plies extending from the end to the radially inner side of the outer end of the belt layer in the tire radial direction. The tubeless tire according to claim 1.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a meridional section of the tire in a normal state and a no-load state where the rim is assembled to the normal rim J and the normal internal pressure is charged.

The "regular rim" is a rim defined for each tire in a standard system including the standard on which the tire is based. For example, "standard rim" for JATMA and "Design Rim" for TRA Rim "or ETR
If it is TO, it will be "Measuring Rim". The "normal internal pressure" is the air pressure specified for each tire in the standard system including the standard on which the tire is based. For JATMA, the "maximum air pressure" and for TRA, the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION P
RESSURES ", the maximum value in ETRTO," INFL
ATION PRESSURE "and 1 when the tire is a passenger car.
80 kPa.

Tubeless tires (hereinafter simply referred to as “tires”)
1) includes a tread portion 2, a pair of sidewall portions 3 extending inward in the tire radial direction from both ends thereof, and a pair of bead portions 4 located at an inner end of each sidewall portion 3. 1 illustrates a radial tire for a passenger car provided with the tire.

The tire 1 includes a carcass 6 extending between the bead cores 5 of the bead portions 4 and 4, a carcass 6 disposed outside the carcass 6 in the tire radial direction and inside the tread portion 2, and two steel sheets. It comprises a belt layer 7 composed of belt layers 7A and 7B, and a bead apex rubber 8 made of hard rubber and extending outward from the outer surface of the bead core 5 in the tire radial direction.

The carcass 6 includes a toroidal ply body 6a extending from the tread portion 2 to the bead core 5 of the bead portion 4 through the sidewall portion 3;
and a single carcass ply 6A integrally having a ply turn-up portion 6b that is folded back from the inside to the outside in the tire axial direction around the bead core 5 and continues to a.

The carcass ply 6A forms a tire bore surface i by the ply body 6a. That is, the tire 1 of the present example does not include an inner liner different from a carcass that has been conventionally generally used, so that the ply main body portion 6a of the carcass ply 6A forms a tire lumen surface i. .

As shown in FIG. 2, the carcass ply 6A comprises a code array 10 in which a plurality of carcass cords 10A are arranged, and a topping rubber 11 covering both sides of the code array 10. You. As the carcass cord 10A, an organic fiber cord such as nylon, rayon, polyester, aromatic polyamide, or vinylon is preferable. Further, the tire 1 of the present example has a radial structure in which the carcass cords 10A are arranged at an angle of 75 to 90 degrees with respect to the tire equator C.

The topping rubber 11 is provided only in the area where the ply main body 6a is formed, and only the inner topping portion 11i forming the tire cavity surface i is covered with the rubber base material 10a.
It is made of butyl rubber containing 10 parts by weight or more of butyl rubber or its derivative in 0 parts by weight. Butyl rubber (IIR) is a copolymer of isobutylene and a small amount of isoprene. Derivatives thereof include, for example, chlorinated butyl rubber, brominated butyl rubber, and the like, which are obtained by reacting the butyl rubber with chlorine, bromine, or the like to improve moldability. Halogenated butyl rubber.

This butyl rubber contains natural rubber (NR) and / or butadiene rubber (B
R) and a diene rubber such as styrene butadiene rubber (SBR). In addition, a filler such as a reinforcing agent such as carbon black, a vulcanizing agent, a vulcanization accelerator, and a softening agent can be added to the rubber base material in the same manner as a general topping rubber.

On the other hand, a rubber portion other than the inner topping portion of the topping rubber, in this example, the outer topping portion 11o
As in the prior art, a non-butyl rubber containing 90 parts by weight or more, preferably 100 parts by weight, of the diene rubber or the like in 100 parts by weight of the rubber substrate is used. Therefore, the adhesion to the side rubber 3G or the like disposed on the side wall portion 3 is improved.

As described above, the inner topping portion 11i made of butyl rubber, which is hardly permeable to air, is
, The carcass ply 6 can also have the function of the conventional inner liner, the conventional inner liner provided separately from the carcass can be eliminated, and a significant reduction in tire weight can be achieved. .

Here, in order for the carcass ply 6A to exhibit sufficient internal pressure holding performance, the content of butyl rubber or a derivative thereof in the butyl rubber is required to be 10 parts by weight or more as described above. It is preferable that the content be 30 parts by weight or more in order to further enhance the air impermeability.

Also, as shown in FIG.
In 1i, the coating thickness Ti from the carcass cord 10A to the tire lumen surface i is preferably set, for example, in the range of 0.2 to 1.0 mm. This inner topping part 11
If the coating thickness Ti of i is less than 0.2 mm, the internal pressure holding performance may be relatively reduced. This coating thickness Ti
When it exceeds 1.0 mm, the butyl rubber has low rebound resilience as described above and is inferior in characteristics as a rubber elastic body.
The elasticity and rigidity of the tire may be impaired, and the balance between the actual vehicle performance, especially the steering stability and the riding comfort may be deteriorated, and an unnecessary increase in tire weight is likely to occur.
From such a viewpoint, the lower limit of the coating thickness Ti is set to 0.1.
More preferably, it is 3 mm or more, and the upper limit is 0.8 mm or less.

As shown in FIG. 3A, a critical surface E between the inner topping portion 11i and the outer topping portion 11o passes through the code array 10 and is formed, for example, on the center line N of the carcass cord 10A. In addition, as shown in FIG. 7B, it may be formed so as to be deviated to the outside of the tire from the center line N or to the inside of the tire as shown in FIG. From the viewpoint of the balance between the steering stability and the ride comfort, or the adhesiveness to the carcass cord 10A, the upper limit of the rubber thickness T from the tire lumen surface i to the critical surface E of the inner topping portion 11i is: When the carcass cord diameter is D,
It is preferable to set Ti + 0.5D or less and 1.5 mm or less.

In the present invention, the folded end portion 6be of the ply folded portion 6b of the carcass ply 6A whose inside is topped with such a butyl rubber is set to be larger than the outer end 8e of the bead apex rubber 8 in the tire radial direction. It is located inside the tire radial direction.

The portion reinforced by the hard bead apex rubber 8 has a smaller bending strain of the tire 1 than other portions. In the tire of the present invention, by positioning the folded end portion 6be of the ply folded portion 6b in such a small distortion portion, separation at the folded end portion can be suitably prevented, and durability can be improved.

The bead apex rubber 8 is preferably formed of a hard rubber having a tapered cross section outward in the tire radial direction, for example, having a JISA hardness of 65 to 95 °, more preferably 70 to 90 °. Further, the outer end 8e is between 0.15 and 0.1 mm of the tire section height H from the bead base line BL.
It is desirably located at a height Ha of 55 times, preferably 0.15 to 0.30 times. The "bead base line" is defined as a tire axial line passing through a rim diameter position defined by the standard on which the tire is based, and the tire section height H is defined as the bead base line B in the normal state and under no load.
The height from L to the outermost side in the tire radial direction.

In order to more suitably prevent the folded end 6be of the ply folded portion 6b from being separated, the tire radius between the outer end 8e of the bead apex rubber 8 and the folded end 6be of the ply folded portion 6b is determined. It is desirable that the distance h in the direction is 5 mm or more, preferably 10 mm or more, and more preferably 10 to 25 mm.

By appropriately limiting the positions of the folded ends 6be of the carcass ply 6A as described above, the weight of the tire can be reduced and the durability can be improved. A single-layer auxiliary cord ply 13 is provided outside the toroidal carcass 6 in order to suppress the deterioration of the actual vehicle performance due to the influence.

The auxiliary cord ply 13 is formed by covering both sides of a cord array in which cords are arranged with a topping rubber made of non-butyl rubber. Further, the auxiliary cord ply is formed of the outer end 8e of the bead apex rubber.
Has an end 13e at a position spaced 10 mm to 15 mm from the outside in the tire radial direction. One of the features is that it extends from the end 13e outward in the tire radial direction at least to the radially inner side of the outer end of the belt layer 7 in the tire radial direction. By providing such an auxiliary cord ply 13, the lateral stiffness of the tire is increased, and the actual vehicle performance, particularly the steering stability,
Ride comfort can be improved in a well-balanced manner.

The tubeless tire of the present embodiment is a tire having a so-called (2-0 HTU) structure, in particular, a two-ply carcass, and the folded height of one ply is radially outside the outer end of the bead apex rubber. While achieving the same level of steering stability and ride comfort, it is possible to significantly reduce the weight compared to such tires.

The end 13 of the auxiliary cord ply 13
The reason why the position of the end 13e is limited is that if the position of the end 13e extends too far inward in the radial direction of the tire, the weight of the auxiliary cord ply 13 increases, which hinders the weight reduction of the tire. If 13e is too far away from the outer end 8e of the bead apex rubber 8 in the radial direction of the tire, improvement in steering stability and the like cannot be expected. Further, even when the auxiliary cord ply 13 does not extend to the inside of the outer end of the belt layer 7, the steering stability cannot be sufficiently improved. "It extends inside the outer edge of the belt layer"
Means that the auxiliary cord ply 13 has the edge 7e of the belt layer 7
Inward in the tire axial direction.

In the structure shown in FIG. 1, the auxiliary cord ply 13 is formed by a single continuous ply 13A extending continuously between the ends 13e. Further, as shown in FIG. 4, a pair of left and right cut-off plies 13B extending from the end 13e to the inner end in the tire radial direction of the outer end of the belt layer 7 can be formed.
Although the steering stability is more preferable in the structure of FIG. 1, when the break ply 13B of FIG.
A so-called hollow structure is formed between 3U and 13U (only one side is shown), and the weight is further reduced. In addition, since the highly rigid belt layer 7 is disposed in the hollow portion, the steering stability is hardly reduced, which is preferable. The structure shown in FIG. 4 is the same as that shown in FIG.
Is the same as

In the present embodiment, the cord of the auxiliary cord ply 13 is made of the same material and the same fineness as the carcass cord 10A. Further, it is desirable that the number of the driving is the same as that of the carcass ply. Further, the cords of the auxiliary cord ply 13 are preferably arranged radially. More preferably, the cord angle of the auxiliary cord ply 13 is preferably inclined to the tire equator C within the same angle range as that of the carcass cord 10A, and intersects the carcass cord 10A when it is other than 90 ° with respect to the tire equator. It is preferable that they face each other.

Although the present embodiment has been described in detail above, such a tire can improve the steering stability and the riding comfort as a whole in a well-balanced manner, and can achieve weight reduction without impairing durability. . Further, the present invention is not limited to the passenger car, and may be preferably formed, for example, for a motorcycle or a small truck.

[0036]

EXAMPLE A tubeless tire for a passenger car having a tire size of 195 / 65R14 and having the configuration shown in FIGS. 1 and 4 was prototyped based on the specifications shown in Table 1, and the tire weight, air permeability resistance, and productivity of each sample tire were tested. , Durability, and actual vehicle performance (driving stability, ride comfort) were tested. For comparison, a tire having a conventional inner liner and the like were also tested and the performance was compared. The test conditions are as follows.

(1) Tire Weight The weight per tire was measured, and was indicated by an index with Comparative Example 2 being 100. The smaller the value, the lighter.

(2) Air Permeation Resistance The tire is assembled on a specified rim (6JJ × 14), filled with a specified internal pressure (200 kPa), and allowed to stand in an oven at 80 ° C. for 15 days. The rate of decrease was measured, and the reciprocal thereof was indicated by an index with Comparative Example 2 being 100.
The larger the value, the better the air permeation resistance.

(3) Productivity The process time required to form a green tire was determined by comparing the process time required in Comparative Example 2.
Is set to 100 and the index is shown. The smaller the value, the better the productivity.

(4) Performance of actual vehicle Tires are assembled on a specified rim (6JJ × 14) and a passenger car (2000 cc / F) is set at a specified internal pressure (200 kPa).
F) was mounted on all wheels, and ran on the test course. At this time, characteristics relating to steering wheel responsiveness, rigidity, grip and the like were indicated as steering stability by a ten-point evaluation by a sensory evaluation by a driver. The larger the value, the better the steering stability. On a step road, a Beljaso road (cobblestone road surface), a Bitzman road (a road surface covered with pebbles) and the like on a test course, a sensation of ruggedness, pushing up, and damping were evaluated as a ride comfort, and a ten-point evaluation was given by a sensory evaluation of a driver. . The larger the value, the better the ride comfort. Table 1 shows the results of the test, and Table 2 shows rubber compounding examples of the topping rubber of the carcass ply.

[0041]

[Table 1]

[0042]

[Table 2]

As a result of the test, the tire of the embodiment can exhibit the same air permeation resistance as the conventional tire, and also reduces the tire weight and reduces the durability by eliminating the inner liner provided separately from the conventional carcass. It was confirmed that it could be improved. There was no problem with the actual vehicle performance.

On the other hand, in Comparative Example 1, the steering stability is low. In Comparative Example 2, there is a large problem in tire weight and productivity. Similarly, the durability was poor in Comparative Example 3, the steering stability was poor in Comparative Example 4, and the productivity was poor in Comparative Example 5, and the balance was poor in all cases.

[0045]

As described above, according to the first, second or third aspect of the present invention, the inner topping portion made of butyl-based rubber, which is hardly permeable to air, surrounds the tire cavity, so that the carcass ply can be provided with the conventional structure. The function of the inner liner can be combined, the conventional inner liner provided separately from the carcass can be eliminated, and the weight of the tire can be significantly reduced. Also, the part reinforced with hard bead apex rubber has less bending distortion of the tire than the other parts, and the separation etc. by positioning the folded end of the ply folded part in such a small part of the distortion It can be suitably prevented, and the durability can be improved without being affected by insufficient adhesive strength of the butyl rubber. Further, by providing the auxiliary cord ply topped with non-butyl rubber, it is possible to improve the actual vehicle performance, especially the steering stability, the riding comfort, etc. in a well-balanced manner while maintaining the weight reduction and durability.

According to the fourth aspect of the present invention, the auxiliary cord ply is formed of a pair of left and right interrupted plies extending from the end to the radially inner side of the outer end of the belt layer in the tire radial direction. To be more effective.

[Brief description of the drawings]

FIG. 1 is a sectional view of a tire showing one embodiment of the present invention.

FIG. 2 is a perspective view showing a structure of a carcass ply.

FIGS. 3A to 3C are cross-sectional views showing a state of a critical surface of a rubber cavity in a topping rubber.

FIG. 4 is a cross-sectional view of a tire showing another embodiment of the present invention.

[Explanation of symbols]

 2 Tread part 3 Side wall part 4 Bead part 5 Bead core 6 Carcass 6A Carcass ply 6a Ply body part 6b Ply fold back part 7 Belt layer 10 Code array body 10A Carcass cord 11 Topping rubber 11i Inside topping part 11o Outside topping part i Tire bore

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[Procedure amendment]

[Submission date] January 17, 2000 (2000.1.1)
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

According to a first aspect of the present invention, there is provided a carcass extending between bead cores of a bead portion, and a belt disposed radially outside the carcass and inside a tread portion. A layer and a bead apex rubber made of hard rubber and extending radially outward from the outer surface of the bead core in the tire radial direction, wherein the carcass extends from the tread portion to the bead core of the bead portion via the sidewall portion. The carcass ply is composed of a ply body portion and a single carcass ply integrally formed with a ply folded portion that is continuous with the ply body portion and is folded around the bead core from the inside to the outside in the tire axial direction, and the carcass ply is a ply body portion. And the folded end of the ply folded portion is beaded Range in the tire radial direction inner side and 10mm~25mm than the radially outer end of the Apex rubber
Is located in enclosed, yet the carcass ply, a code array having an array of carcass cords a plurality of, consists of a topping rubber which covers both sides of the code array, and the topping rubber, the ply main body portion only the inner topping portion forming the additionally provided to the inner tire cavity surface to a range which forms, a butyl rubber or a derivative thereof so as to form butyl rubber containing more than 10 parts by weight base rubber in 100 parts by weight, the inner Carcass of topping rubber part
The coating thickness Ti from the cord to the tire bore surface is 0.2mm
~ 0.8 mm, and, outside the carcass, provided an auxiliary cord ply covered with a topping rubber made of non-butyl rubber on both sides of the cord array body in which the cords are arranged,
And this auxiliary cord ply has an end at a position spaced from the outer end of the bead apex rubber by 10 to 15 mm radially outward from the outer end of the bead apex rubber, and at least radially inward of the outer end of the belt layer in the tire radial direction. It is a tubeless tire characterized by being stretched.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008] According to a second aspect of the invention, the bead apex rubber, as characterized in that the outer end is located from the bead base line to 0.15 to 0.55 times the height of the tire section height H I have .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

The invention according to claim 3 is characterized in that the auxiliary cord ply is formed of one continuous ply extending continuously through the tread portion across the end portions.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

Also, as shown in FIG.
In 1i, the coating thickness Ti from the carcass cord 10A to the tire lumen surface i is preferably set, for example, in the range of 0.2 to 1.0 mm. This inner topping part 11
If the coating thickness Ti of i is less than 0.2 mm, the internal pressure holding performance may be relatively reduced. This coating thickness Ti
When it exceeds 1.0 mm, the butyl rubber has low rebound resilience as described above and is inferior in characteristics as a rubber elastic body.
The elasticity and rigidity of the tire may be impaired, and the balance between the actual vehicle performance, especially the steering stability and the riding comfort may be deteriorated, and an unnecessary increase in tire weight is likely to occur.
From such a viewpoint, the lower limit of the coating thickness Ti is set to 0.1.
It is 2 mm or more, and the upper limit is 0.8 mm or less .

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction contents]

[0028] Then, the folded end portion 6be of the ply turnup portion 6b in order to more favorably prevent the separation, the tire radial direction of the folded end portion 6be of the outer end 8e and the ply turnup portion 6b of the bead apex rubber 8 Is 10 to 25 mm .

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction contents]

In the structure shown in FIG. 1, the auxiliary cord ply 13 has a tread portion extending across the end portions 13e.
Shows those formed by a single continuous ply 13A extending continuously street. Further, as shown in FIG. 4, a pair of left and right cut-off plies 13B extending from the end 13e to the inner end in the tire radial direction of the outer end of the belt layer 7 can be formed. In the structure of FIG. 1, the steering stability is more preferable. However, when the break ply 13B of FIG. 4 is used, a so-called hollow structure is formed between the break ends 13U and 13U (only one side is shown), so that the weight is lighter. It will be excellent in conversion. In addition, since the highly rigid belt layer 7 is disposed in the hollow portion, the steering stability is hardly reduced, which is preferable. The structure of FIG. 4 is the same as that of FIG. 1 except for the configuration of the reinforcing cord ply 13.

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Claims (4)

[Claims] 1. A carcass extending between bead cores of a bead portion, a belt layer disposed outside the carcass in a tire radial direction and inside a tread portion, and made of hard rubber and extending in a tire radial direction from an outer surface of the bead core. A tubeless tire provided with a bead apex rubber extending outward, wherein the carcass is a ply body portion extending from a tread portion to a bead core of a bead portion through a sidewall portion, and the periphery of the bead core connected to the ply body portion. The carcass ply is formed of a single carcass ply integrally having a ply turn-up portion turned from the inside to the outside in the tire axial direction, and the carcass ply forms a tire cavity surface by a ply main body and a turn-up end of the ply turn-up portion The tire of the bead apex rubber is larger than the tire radial outer end. The carcass ply is located radially inward, and the carcass ply is composed of a code array in which a plurality of carcass cords are arranged, and a topping rubber covering both sides of the code array, and the topping rubber is a ply body. Only the inner topping part which is attached to the part forming area and forms the tire inner surface is formed of butyl rubber containing 10 parts by weight or more of butyl rubber or a derivative thereof in 100 parts by weight of the rubber base material, On the outside of the carcass, an auxiliary cord ply is provided in which both sides of a cord array in which cords are arranged are covered with a non-butyl rubber topping rubber, and the auxiliary cord ply is a tire from the outer end of the bead apex rubber. It has an end at a position radially outward at a distance of 10 to 15 mm, and at least an outer end of the belt layer. A tubeless tire that extends inward in the tire radial direction. 2. The method according to claim 1, wherein the bead apex rubber has an outer end of 0.15 of a tire sectional height H from a bead base line.
The tire is located at a height of about 0.55 times, and a distance h in a tire radial direction between an outer end of the bead apex rubber and a folded end of the carcass ply is 5 mm or more. Tubeless tire. 3. The tubeless tire according to claim 1, wherein the auxiliary cord ply is formed of one continuous ply extending continuously between the end portions. 4. A pair of left and right interrupted plies extending from the end to the radial inner side of the outer end of the belt layer in the tire radial direction and being interrupted. Tubeless tires.