JP2002172918A - Safety pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety tire with an incorporated air bladder formed that a punctured pneumatic tire having a low manufacturing cost and the slight increase in a weight and an air bladder can run safely a long distance without the occurrence of a failure in operation. SOLUTION: In a safety pneumatic tire having combination of a pneumatic tire and an incorporated air bladder, a reinforcing layer is formed at the air bladder along a peripheral direction. In the tread part earth region for rolling of an application load of an assembly of the safety pneumatic tire, where the pneumatic tire and the air bladder are individually filled with an internal pressure, and a rim, the air bladder has an outer peripheral surface to hold a gap between an reinforcing layer, serving as an outside diameter growth suppression member, and a tread part inner surface. Characteristics are provided that when only the inner pressure of the pneumatic tire is gauge pressure being zero, the reinforcing layer is elongated by 15% or more in a peripheral direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety pneumatic tire capable of continuing a safe running even in a puncture state for a predetermined distance, in particular, a pneumatic tire having a radial carcass, and a tire tube separately incorporated therein. A safety pneumatic tire having a combination with an air cushion.

[0002]

2. Description of the Related Art Even if a pneumatic tire is punctured, it can be continued until it is equipped with facilities that allow tire replacement.
In order to respond to the demand for safe pneumatic tires or run-flat tires that can safely travel a predetermined distance, various specially structured tires, tire tube-shaped airbags, and various special tire assemblies have been proposed. I have.

[0003] For example, as for the tire itself, there are tires in which a sealant is applied to the inner surface of a tread portion.
There are various types of airbags inserted into the tire, such as reinforced airbags, multi-chamber airbags, foam or sponge-filled airbags, and folded airbags.
Known tire assemblies include a foamed or sponge-filled tire assembly, a core assembly built-in tire assembly, and the like.

[0004] In particular, as an example of a recent assembly of a built-in tire and a rim of a reinforced airbag, see International Publication Pamphlet WO9.
In Japanese Patent Application Laid-Open No. 8/23457, a belt of two layers of cord cross layers similar to a tire is provided as a reinforcing member on the outer periphery of a pneumatic tire, and the internal pressure of the pneumatic tire is set to be 50% lower than the internal pressure of the pneumatic tire.
When a pneumatic tire is punctured by using the pneumatic tire by increasing the pressure by up to 500 kPa, a safety pneumatic tire has been proposed in which the airbag expands to break the cord of the restraining reinforcing material, thereby replacing the load bearing of the pneumatic tire.

[0005] International publication pamphlet WO99 / 3
No. 2308 proposes a dual tire type safety pneumatic tire in which an outer pneumatic tire and an inner torus-like tire (airbag) similar to the radial tire structure incorporated therein are assembled to a rim together. The gist is that the inside airbag is provided with a plurality of reinforcing annular elements (cords) that are separated in the width direction on the outer periphery, and when the outer pneumatic tire is punctured, the airbag expands due to the expansion force of the airbag. The annular cord breaks, and the airbag replaces the load bearing of the pneumatic tire.In these respects, the disclosed tires of both types are superior in safety pneumatic tires compared to the conventional type. It is.

[0006]

However, nonetheless, the safety pneumatic tires disclosed in the above-mentioned International Publication Pamphlets have a high manufacturing cost of the airbag and the latter has a carcass. As a result, the weight of the safety pneumatic tire has increased remarkably, and there is still room for improvement in the reduction of fuel efficiency. In particular, when the applicable vehicle is a passenger car, it cannot be ignored that the increase in weight increases the unsprung weight and lowers the vibration riding comfort performance.

[0007] Further, of the airbags disclosed in both the International Publication Pamphlets, the cord breaks inside the airbag during a safe driving distance required for a punctured pneumatic tire, for example, 50 km. While the broken cord ends have the potential to damage the airbag itself, destroying it and compromising the function of a safe pneumatic tire,
If the cord breaks outside the air bag, there is room for improvement in that the broken cord may damage the inner surface of the pneumatic tire including the carcass.

Therefore, the inventions described in claims 1 to 18 of the present invention are based on the premise that the tire is of the air-built-in tire type, and it is possible to minimize the increase in the production cost and weight of the air sac to a minimum. Safety pneumatic that can run through the above-mentioned safe driving distance with a sufficient margin without causing any failure in both the pneumatic tire and the airbag when a puncture occurs in the pneumatic tire The purpose is to provide tires.

[0009]

In order to achieve the above-mentioned object, an invention according to a first aspect of the present invention is an air supply system having a tread portion, a pair of sidewall portions and a pair of bead portions connected to both sides thereof. In a safety pneumatic tire having a combination of a pneumatic tire and a tire tube-shaped pneumatic tire separately housed therein, the pneumatic tire includes a reinforcing layer disposed in a circumferential direction of the pneumatic tire to rim the pneumatic tire. The pneumatic tire and the pneumatic tire are reinforced at the tread contact area in the rolling state where the load of the safety pneumatic tire and rim assembly is filled with the specified internal pressure separately for the pneumatic tire and the pneumatic tire. The layer has an outer peripheral surface that keeps a gap between the inner surface of the tread portion and the outer surface of the layer as an outer diameter growth suppressing member that resists centrifugal force. Of time, the reinforcing layer is a secure pneumatic tire characterized by having a characteristic of extending the circumferential direction of 15% or more.

According to the first aspect of the present invention, there is provided a second aspect.
As in the invention described in (1), the airbag is provided with one
According to another aspect of the present invention, there is provided an airbag according to claim 3, wherein the airbag includes one or more circumferential continuous reinforcing layers extending between its maximum width positions. A directional continuous reinforcing layer is provided, and apart from the inventions described in claims 2 and 3, as in the invention described in claim 4, in the above-described assembly, the airbag is a pair of pneumatic tires. One on each side face facing each sidewall
It has a circumferential continuous reinforcement layer of more than layers.

According to the invention described in claims 1 to 4, as in the invention described in claim 5, in the above assembly, the airbag has an internal pressure equal to or higher than the internal pressure of the pneumatic tire.

According to the invention described in claims 1 to 5, when only the internal pressure of the pneumatic tire in the assembly is zero in gauge pressure as in the invention described in claim 6, the load on the assembly is reduced. In the tread portion ground contact region in the rolling state, the reinforcing layer has an elongation characteristic that allows the tread portion to be inscribed in the airbag within the elastic limit.

Further, according to the invention described in claims 1 to 6, as in the invention described in claim 7 or 9, the reinforcing layer has at least one layer of a composite of a fiber and a rubber composition. Or, the reinforcing layer has one or more resin layers, and relates to the invention described in claims 1 to 7, and as in the invention described in claim 8, the reinforcing layer is formed of a fiber and a rubber composition. The composite layer is formed by laminating in a range of 2 to 7 layers,
According to the invention described in claim 9, as in the invention described in claim 10, the reinforcing layer has a thickness in the range of 0.05 to 2.0 mm per layer, and the one reinforcing layer is made of rubber. The composition comprises fibers having a maximum diameter in the range of 0.0001 to 0.2 mm and a length of 8 mm or more, and
Regarding the invention described in Item 10, as in the invention described in Item 11, the reinforcing layer contains 3 to 50% by mass of fibers in the rubber composition.

According to the invention described in claims 1 to 11, as in the invention described in claim 12, in the above assembly, the reinforcing layer has a basis weight of 10 to 300 g / m ^{2 in the} rubber composition.
Having a non-woven fabric within the range.

[0015] Further, according to the invention described in the first to sixth aspects, as in the invention described in the thirteenth aspect, the reinforcing layer comprises:
An initial elastic modulus in the range of 0.1 to 1.3 GPa;
It is formed from a resin layer having physical properties of a yield stress in the range of 3 MPa and an elongation at break of 20% or more.

Further, with respect to the invention described in claims 1 to 5 and claim 13, as in the invention described in claim 14,
When only the internal pressure of the pneumatic tire in the assembly is zero as the gauge pressure, the reinforcing layer in the tread portion ground contact area in the load rolling state of the assembly is in a plastically deformed state exceeding the yield point. It has physical properties that enable inscribed treads.

According to the invention as set forth in claims 1 to 12, the reinforcing layer is formed integrally with the airbag as in the invention as set forth in claim 15, or as described in claims 1 to 14. According to the present invention, the reinforcing layer is formed separately from the airbag, and the airbag is joined to the reinforcing layer.

Further, according to the invention described in claims 1 to 16, as in the invention described in claim 17, the tensile elastic modulus of the reinforcing layer at 0-5% elongation in the tire circumferential direction is E (0
5) (kgf / cm), the tensile modulus at 5 to 10% elongation is E
(5-10) (kgf / cm), E (0
５5) / E (5-10) ≧ 2.0 and E (0-5) ≧
5.0 (kgf / cm). Here, the tensile modulus E (0 to 0)
5) (kgf / cm) and E (5-10) (kgf / cm) are the values when the reinforcing layer is given 1% strain at 0-5% elongation and 5-10% elongation, respectively. It is a number.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the examples shown in FIGS. 1 to 3 are cross-sectional views of an assembly of a safety pneumatic tire and a rim according to the present invention. FIGS. 4 and 5 show an assembly of a safety pneumatic tire and a rim shown in FIGS. 1 and 3. FIG. 6 is a cross-sectional view of the assembly shown in FIG. 4 at the time of puncture of the tire when the load is rolling.

1 to 3, a pneumatic tire (hereinafter, referred to as a tire) 2 applied to a safety pneumatic tire (hereinafter, referred to as a safety tire) 1 includes a tread portion 3 and a pair of It has a sidewall portion 4 and a pair of bead portions 5. The safety tire 1 is provided with a tire tube-shaped air bag (air bag, hereinafter referred to as an air bag) 6 incorporated in the tire 2 separately from the tire 2, and the safety of the tire 2 is combined with the air bag 6. The tire 1 is configured. Each of the pneumatic tire and the pneumatic bag is filled with an inert gas such as nitrogen gas according to the user's request without being limited to only the air filling.

1 to 3, the tire 2 is filled with a predetermined air pressure P ₁ (kPa, gauge pressure, the same applies hereinafter) through a valve 8 fixed to a rim 7 specified by the following standard. The airbag 6 is also individually filled with a predetermined air pressure P ₂ (kPa, gauge pressure, the same applies hereinafter) via the valve 9, and the safety tire 1 and the rim 7 are filled under the air pressures P ₁ and P ₂ . An assembly (hereinafter, referred to as an assembly) is configured. The outer diameter of the airbag 6 is set to a value smaller than the inner diameter of the inner surface 3is of the tread portion 3 of the tire 2. The air pressure P ₁ is a maximum air pressure defined by the following standards, and the air pressure P ₁ and the air pressure P ₂ satisfy a relationship of P ₁ ≦ P ₂ . The valves 8 and 9 may be integrated into one, and the air passage may be branched into two by one valve.

That is, JATMA YEAR BOOK (2000), ETRT
O STANDARD MANUAL 2000, TRA (THETIRE and RIM ASSOCI
ATION INC.) 'S 2000 YEAR BOOK standards.
If represented by ATMA YEAR BOOK, the rim is the applicable rim described in the general information, and specifically, the table of applicable rims by tire type (APPROVED RIM CONTOUR in ETRTO and TRA)
According to the rim size described in S), the maximum air pressure (gauge pressure, the same applies hereinafter) and the maximum load capacity described below are listed in the "Pneumatic-load capacity correspondence table" for each tire type (similar table for TRA, tire size for ETRTO) Table), the maximum air pressure (kPa) and the corresponding maximum load capacity (mass kg)
It is.

Here, the reinforcing layer 10 is arranged along the circumferential direction of the airbag 6. In FIGS. 4 and 5, under the rolling condition on the flat road surface Sr of the assembly to which the load L is applied,
The airbag 6 in the ground area of the tread portion 3 serves as an outer diameter suppressing member that opposes the centrifugal force generated by the rotation of the reinforcing layer 10,
It has an outer peripheral surface that maintains a gap δ (mm) between the inner surface 3 is of the tread portion 3. 4 and 5, the gap δ (mm) at the position of the equator plane E of the tire 2 is shown as a representative.
Although the dimensions vary somewhat along the width direction of the reinforcing layer 10, it extends over the entire inner surface 3is. The air bag 6 of the assembly shown in FIG. 2 also maintains the gap δ, although not shown.

The rolling state is defined as the maximum load capacity corresponding to the maximum air pressure of the tire 2 according to the above standard of 0.8 to 0.8.
Load L equivalent to 1.3 times, for example, 1.0 times
(N) is loaded on the assembly, and the assembly is
/ h, for example, at a speed of 100 km / h.

First, in the contact area of the tread portion 3 inside the assembly traveling at the above speed under the load L, the reinforcing layer 10 as an outer diameter growth suppressing member against centrifugal force is used. The radial growth of the air bag 6 on which the centrifugal force acts while traveling at the above speed is suppressed, and the gap δ is always formed between the outer peripheral surface of the air bag 6 and the inner surface 3is of the tread portion 3, so that the air The outer peripheral surface of the sleeve 6 (the outer peripheral surface of the reinforcing layer 10) does not rub against the inner surface 3is of the tread portion 3, and as a result, damage to the airbag 6 itself and the tread 3
There is no damage to the inner surface 3is.

Further, by providing the reinforcing layer 10, the outer diameter of the air bag 6 is set to be large within a range for maintaining the gap δ, and the expansion of the air bag 6 is suppressed. the P ₂ higher than the internal pressure (air pressure) P _1, the differential pressure P ₂
−P ₁ = ΔP can be set to a sufficiently high value to increase the amount of air inside the airbag 6, and as a result, the amount of deflection of the tire 2 during puncturing can be kept to a minimum, which is advantageous in improving durability. Can be realized.

On the other hand, assuming that some of the reference numerals are used from FIG. 4, a conventional air-built safety tire made of only rubber and having an outer diameter smaller than the inner surface diameter of the tread portion 3 of the tire 2 is described. The airbag inside the assembly traveling at the above speed under the load L protrudes outward in the radial direction of the tire 2 due to the centrifugal force caused by the rotation, and the inner surface of the tread 3 at the contact area of the tread 3 During the long distance running, damage to the inner surface 3is of the tread portion 3 and damage to the air sac itself occur, and eventually, when the tire 2 is punctured, the air sac may be punctured at the same time. It is expensive and cannot reliably fulfill the role of a safety tire. In addition, if the size and the internal pressure are set within a range in which the airbag does not rub, the tire 2 at the time of puncture has a significantly large deflection,
Sufficient durability cannot be obtained.

Next, in FIG. 6, the tire 2 is driven for a long distance.
The airbag 6 which is intact even if it goes is the internal pressure P _TwoWhile holding
Then, external factors such as nail stepping or internal factors such as failure of valve 8
Pressurized air inside the tire 2 flows out due to factors
Internal pressure P of ear 2₁Becomes 0 (zero) in gauge pressure,
That is, when the external pressure of the airbag 6 becomes zero in gauge pressure,
The reinforcing layer 10 provided in the airbag 6 has one circumferential direction.
It is assumed that the reinforcing layer 10 has a property of extending 5% or more,
It does not break or break. This makes the airbag 6
Expands inside the flat tire 2 shown in FIG.
The outer periphery of the airbag 6 is inscribed in the inner surface 3is of the tread 3
In FIG. 6, the airbag 6 inscribes the entire inner surface of the tire 2,
The load L of the tire 2 is taken over.

As described above, the airbag 6 provided with the reinforcing layer 10 damages both the tire 2 and the airbag 6 while the tire 2 travels a long distance while maintaining the internal pressure P _1. No, and when the tire 2 is punctured, the reinforcing layer 10 only elongates, so the predetermined distance, e.g.
At 0 km, both the tire 2 and the airbag 6 are maintained in a normal state without causing any fatal damage, and the safety tire 2 can be completed. Also, external pressure (gauge pressure) P ₁ is a reinforcing layer 10 which serve the purpose as long as it has the property of stretching more than 15% under the action of internal pressure P ₂ at zero gauge pressure, only slightly using low cost materials Therefore, the production cost of the air bag 6 is low, and the increase in weight can be minimized.

Hereinafter, the details of the airbag 6 and the reinforcing layer 10 will be described. In FIG. 1, an air bag 6 has one or more layers around its outer periphery, and in the illustrated example, one reinforcing layer 10 which is continuous in the circumferential direction.
Is provided. This reinforcing layer 10 has a width substantially equal to the entire outer peripheral width of the airbag 6. In FIG.
Is provided with one or more layers extending radially outward between positions A having the maximum width Wmax, and in the illustrated example, one reinforcing layer 10 which is continuous in the circumferential direction is provided. These reinforcing layers 10, at the ground-contact region of the tread portion 3, acts as a direct centrifugal force opposing member of the air bladder 6 internal pressure P ₁ is in the normal, and when the internal pressure P ₁ is zero gauge pressure, the internal pressure It serves as a direct radial growth permitting member of the air bladder 6 due to the action of P _2.

On the other hand, the air bag 6 shown in FIG.
The tire 2 is provided with one or more layers, in the illustrated example, one reinforcing layer 10 continuous in the circumferential direction on each of both side surfaces facing the pair of sidewall portions 4. This type of reinforcing layer 10
Serves as an indirect centrifugal opposition member of the airbag 6 and as part of the radial growth member of the airbag 6.

In FIG. 6, when only the internal pressure P ₁ is zero in gauge pressure, the reinforcing layer 10
The air bag 6 has an elongation characteristic that allows the inflating of the tread portion 3 of the air bag 6 within the elastic limit, and depending on the material applied to the reinforcing layer 10, the air bag 6 is in a plastically deformed state exceeding the yield point. And a case in which the tread portion 3 has physical properties that allow inscribedness. In any case, the reinforcing layer 10 can be inscribed in the tread portion 3 of the air bag 6 before breaking.

The reinforcing layer 10 may be extended to the contact surface with the rim 7 if necessary. At this time, the number of layers is reduced from the outer peripheral portion to the portion near the rim 7. In this manner, when the safety tire 1 is mounted on the rim 7 by extending the contact surface with the rim 7, the airbag 6 can be prevented from biting between the tire 2 and the rim 7. In addition, there is an effect that the airbag 6 inside the tire 2 is more stably held and the valves 8 and 9 are reinforced.

The reinforcing layer 10 can be formed from one or more layers of a composite of a fiber and a rubber composition, and can be formed from one or more resin layers. When using the layers of this composite, the reinforcing layer 10 is preferably formed by lamination in the range of 2 to 7 layers. First, the reinforcing layer 10 of the composite will be described.

Fibers used for the composite include natural polymer fibers such as cotton and cellulose, aromatic polyamide fibers, aliphatic polyamide fibers, polyester fibers, polyvinyl alcohol fibers, rayon fibers, polyolefin ketone fibers,
Synthetic polymer fibers such as polybenzoxazole fibers and inorganic fibers such as glass fibers, carbon fibers, and steel fibers are suitable. As aromatic polyamide fiber,
Examples include polyparaphenylene terephthalamide, polymetaphenylene terephthalamide, polyparaphenylene isophthalamide, and polymetaphenylene isophthalamide. These fibers may be used alone or in combination of two or more. The cross section of these fibers is circular, oval,
Any shape such as a polygon is acceptable, and fibers having a hollow portion may be used. Further, a composite fiber having a core-sheath structure, a U-shape, a petal shape, a lamellar shape, or the like in which different materials are applied to the inner layer and the outer layer may be used.

These fibers exist both when used alone and when used as a nonwoven fabric. In addition, these fibers have improved rigidity by themselves when the rubber composition enters, and may not be particularly bonded to the matrix rubber.However, in order to further increase the bonding effect, the fibers are subjected to an adhesive treatment. Is also good.

The rubber component of the rubber composition used in the composite does not need to be particularly limited. Among them, natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), isoprene rubber ( A diene rubber such as IR) is suitable. Further, the rubber composition is stress M ₅₀ Tensile at 50% elongation in the range of 1.0～9.0MPa, stress M ₁₀₀ Tensile at 100% elongation 2.0 to 1
It is preferably in the range of 5.0 MPa.

When the reinforcing layer 10 is formed from a layer of the above composite, the reinforcing layer 10 has a thickness in the range of 0.05 to 2.0 mm per layer. When the thickness is less than 0.05 mm, it becomes difficult to uniformly distribute the fibers in the rubber composition, and when the strength and rigidity of the reinforcing layer 10 are insufficient, when the thickness exceeds 2.0 mm. Since the effect of the reinforcing layer 10 reaches a plateau and the weight increases remarkably, neither is preferable. One reinforcing layer 10 contains 0.0001 in the rubber composition.
Fibers having a maximum diameter in the range of 0.2 mm and a length of 8 mm or more are contained. The maximum fiber diameter is 0.
If it is less than 0001, the cost will be relatively high, and if it exceeds 0.2 mm, the strength of the reinforcing layer 10 will be insufficient.

The reinforcing layer 10 contains 3 to 5 in the rubber composition.
It contains fibers in the range of 0% by mass. If the fiber content is less than 3% by mass, the effect of increasing the mass on the rigidity-improving effect of the fibers is large, and the function as a member against centrifugal force becomes insufficient. If it exceeds 50% by mass, the content in the rubber composition is reduced. It is difficult to uniformly disperse the fibers, and there is a problem that the rigidity is not uniform between the portion where the rubber composition enters and the portion where the rubber composition does not enter.

When a simple fiber is used for the composite of the rubber composition and the fiber, the fiber is previously mixed into the unvulcanized rubber composition at the stage of the unvulcanized member. More specifically, roles,
Using a kneading device such as a Banbury mixer, the fibers are charged little by little into the unvulcanized rubber composition, and the dispersion of the fibers due to kneading is made uniform.

The reinforcing layer 10 shown in FIGS. 1 to 3 is suitable for having a nonwoven fabric having a basis weight in the range of 10 to 300 g / m ^{2 in} the rubber composition. The nonwoven fabric corresponds to the fiber of the above-described composite. In this case, in the assembly shown in FIGS. 1 to 3, the predetermined internal pressure P ₁ of the tire 2 decreases, and the differential pressure ΔP obtained by subtracting the reduced internal pressure from the predetermined internal pressure P ₂ of the air bag 6 is 200 k.
When the pressure is equal to or higher than Pa, the reinforcing layer 10 has a predetermined internal pressure P _{2 of the} tire _2.
The layer structure of the composite of the nonwoven fabric and the rubber composition, whose weight is reduced by 15% or more as compared with the weight at the time, is suitable for appropriately realizing the effect of the reinforcing layer 10.

For the nonwoven fabric, a manufacturing method by a needle punching method, a carding method, a melt blowing method and a spun bonding method is suitable. Among these manufacturing methods, in particular, a nonwoven fabric manufactured by a carding method in which fibers are entangled with a water stream or a needle and a spun bond method in which fibers are bonded to each other are more suitable.

If the basis weight of the non-woven fabric is less than 10 g / m ^2, it is difficult to maintain the uniformity of the non-woven fabric, the uneven distribution of the fibers becomes large, and the reinforcement comprising the composite of the vulcanized rubber composition and the non-woven fabric is used. While the variation in the strength, rigidity and elongation at break of the layer 10 increases, when the basis weight exceeds 300 g / m ² ,
Although it depends on the fluidity of the rubber composition, the rubber composition hardly penetrates into the voids inside the nonwoven fabric, and the reinforcing layer 10 is easily peeled off from the air sac 6, so that both are incompatible.

When the pressure difference ΔP is 200 kPa or more, it is suitable that the weight loss of the reinforcing layer 10 is 15% or more.

When a nonwoven fabric is used for the composite, the unvulcanized rubber composition sheet is pressed against the nonwoven fabric from both upper and lower surfaces or one surface by a press or a heat roll, and the air inside the nonwoven fabric is mixed with the unvulcanized rubber composition. Substitute enough. When the fluidity of the unvulcanized rubber composition is insufficient, the above-mentioned pressure bonding is performed under a temperature condition within a range where the vulcanization reaction does not occur. Further, as another method, the unvulcanized rubber composition may be liquefied in a solvent and applied to a nonwoven fabric and impregnated, or may be immersed in the liquid unvulcanized composition.

In addition to the nonwoven fabric, it is also suitable to form the reinforcing layer 10 with a composite layer of a number of corrugated steel fibers and a rubber composition. Here, the amplitude and cycle of the waveform are as follows when the internal pressure P _{1 of the} tire 2 is zero as a gauge pressure.
It is set so that the circumferential extension of the reinforcing layer 10 is 15% or more. The steel fiber of the reinforcing layer 10 has a large value of mass% in the rubber composition.

The waveform of the steel fiber may be any of a sine wave shape, a square shape, and a triangular shape. In the rubber composition, one or more of these corrugated steel fibers are spirally wound in the circumferential direction of the air bag 6 to form a composite, or a predetermined number in the width direction of the air bag 6 Either the layers embedded in the rubber composition may be wound together to form a composite with an overlap joint.

Next, the reinforcing layer 10 formed from a resin layer will be described. The resin applied to the reinforcing layer 10 is 0.1.
Initial elastic modulus in the range of 1 to 1.3 GPa and 10 to 33MPa
It is suitable to have the physical properties of the yield stress in the range of a and the elongation at break of 20% or more. As described above, the reinforcing layer 10 made of the resin layer has an elongation characteristic that enables the inner contact of the tread portion 3 of the airbag 6 within the elastic limit when the internal pressure of the tire 2 is zero as the gauge pressure. This includes both the case and the case where the tread portion 3 of the air bag 6 can be inscribed in a state of plastic deformation beyond the yield point.

The reinforcing layer 10 composed of a composite layer is formed integrally with the air bag 6 during the manufacturing process of the air bag 6, or is formed separately from the air bag 6 and is formed with the air bag 6. The reinforcing layer 10 made of a resin layer is formed separately from the air bag 6, and the reinforcing layer 10 is
To join. This is because it is suitable that the air bag 6 except for the reinforcing layer 10 is made of a rubber composition.

Here, the tire 2 is suitable for use in relatively high-speed vehicles or high-speed vehicles such as passenger cars, trucks and buses, which run at relatively high speeds. A tubeless tire is suitable because the tire is more suitably fitted and needs to maintain the air pressure P ₁ between the rim 7 and the airbag 6.

In the safety pneumatic tire configured as described above, the tensile modulus of the reinforcing layer at 0-5% elongation in the tire circumferential direction is E (0-5) (kgf / cm) and 5-10% elongation. Where E (5-10) (kgf / cm) is the tensile elastic modulus at the time, E (0-5) / E (5-10) ≧ 2.0
And when E (0-5) ≧ 5.0 (kgf / cm),
During normal use, due to high elasticity at 0-5% elongation,
In contrast to the internal pressure resistance P ₁ -P ₂ and the centrifugal force, the expansion of the air sac is suppressed, and when the pressure outside the air sac is reduced by puncturing, low elasticity at 5 to 10% elongation. Depending on the area, smooth expansion of the airbag is realized, and run-flat driving of the required distance is realized. During the run-flat running, the airbag is not cut and broken locally, but rather is broken and expanded relatively uniformly in the tire circumferential direction. As a result, early failure during run-flat running can be advantageously prevented.

1 to 3, the tire 2 includes a single ply that reinforces the tread portion 3, the pair of sidewall portions 4, and the pair of bead portions 5 between the bead cores 11 embedded in the pair of bead portions 5. The carcass 12 of the rubber-coated ply having the above radial arrangement code, and the carcass 12
A belt 13 for strengthening the tread portion 3 on the outer periphery of the belt, and an inner liner rubber 14 having excellent air impermeability. Further, the radial carcass 12 is suitable to have a folded portion along the outer peripheral surface of the bead core 11 in order to further ensure the durability of the bead portion 5 during puncturing.

[0053]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The tire 2 applied to the safety tires 1 of Examples 1 to 5 is a radial ply tire for trucks and buses.
Size is 315 / 60R22.5 (described in ETRTO 2000)
The configuration of the tire 2 is as shown in FIGS. 1 to 3. In particular, the carcass 12 has one ply of radially arranged rubber-coated steel cord plies. Table 1 shows the values of the airbag 6 and the reinforcing layer 10 and the filling internal pressures P ₁ and P ₂ . Table 1 also shows Comparative Example Safety Tires 1 incorporating a rubber-only airbag as an evaluation standard of each example safety tire. In each embodiment, application drawings are described.
Table 2 shows details of the reinforcing layers 10 of Examples 1, 4, and 5, and Table 3 shows details of the reinforcing layers 10 of Example 2.

[0054]

[Table 1]

[0055]

[Table 2]

[0056]

[Table 3]

Each safety tire 1 shown in Table 1 (Tables 2 and 3)
A low internal pressure drum test in which the internal pressure P ₁ = 0 and the tire 2 is punctured to maintain the internal pressure P ₂ = 450 kPa;
Internal pressure P ₁ = 900 kPa, P ₂ = 900 kPa, 1000 kPa
Both were subjected to a high internal pressure long ground ram test. The load L was 34.8 kN corresponding to the maximum load capacity, and the speed was 60 km / h. The low internal pressure drum test summarizes the distance traveled before the tire 2 failed, using the index of the comparative example as 100, and the high internal pressure long run test runs until it completes 150,000 km without any problems in the market. The distance was measured, and the results are shown in Table 1. The larger the value, the better. In Table 1, the low internal pressure drum test result is represented as P ₁ = 0 traveling distance, and the high internal pressure long ram test result is represented as P ₁ holding traveling distance.

From the results shown in Table 1, it can be seen that the safety tires 1 of Examples 1 to 5 have improved durability as compared with the safety tires of the comparative example, and that the safety tire 1 at the time of puncture running of the tire 2 is improved. It can also be seen that the durability of the air blast 6 during traveling while maintaining the internal pressure P ₁ is greatly improved from the fact that the air blast of the comparative example failed before the required traveling distance was halfway.

Next, it has the same structure as that of Examples 1, 4 and 5 in Table 1, where E (0-5) / E (5-10) ≧ 2.0 and E
(0-5) ≧ 5.0 (kgf / cm) Examples 6 to 8 concerning normal running durability, presence / absence of breakage of air bubbles, and run flat durability will be described. In addition,
For comparison, E (0-5) / E (5-10) <2.0
Or Comparative Example 2 where E (0-5) <5.0 (kgf / cm)
3 and Comparative Example 4 having no reinforcing layer are also shown.

Here, the normal running durability is as follows:
When a 5 / 60R22.5 tire was mounted on an adaptive rim and the safety pneumatic tire was run at 60 km / h under the condition that the tire load was set to a load equivalent to 1.0 times the maximum load capacity. The distance to the puncture of the pneumatic tire was measured, and the presence or absence of destruction of the air sac was determined by observing the air sac after the normal running durability test and confirming the presence or absence of the destruction. The run-flat running durability was determined by observing the air-seal condition after traveling 5000 km with only the gauge pressure of the pneumatic tire set to 0.

Here, as for the normal running durability and the run flat running durability, Comparative Example 4 is shown as a control, and the larger the value, the better the result. Table 4 shows the results.

[0062]

[Table 4]

According to Table 4, Examples 6 to 8 are all superior to Comparative Examples 2 to 4 in all of the normal running durability, the presence / absence of air bag destruction, and the run flat running durability. It can be seen that the results are as follows.

[0064]

According to the invention described in claims 1 to 17 of the present invention, when the pneumatic tire is punctured under the combination of the pneumatic tire and the built-in pneumatic tire, the circumferential direction of the tire increases by 15%.
By providing a reinforcement layer that extends by at least%, the pneumatic tire does not break down when the pneumatic tire is at normal internal pressure, and the pneumatic tire can travel the required distance sufficiently even when punctured. It is possible to provide a safe pneumatic tire that can be manufactured and that can be manufactured with low manufacturing cost and small weight increase.

[Brief description of the drawings]

FIG. 1 is a sectional view of an assembly of a safety pneumatic tire and a rim according to the present invention.

FIG. 2 is a cross-sectional view of another type of safety pneumatic tire and rim assembly of the present invention.

FIG. 3 is a cross-sectional view of another type of safety pneumatic tire and rim assembly of the present invention.

FIG. 4 is a sectional view just below the load when the load of the assembly of the safety pneumatic tire and the rim shown in FIG. 1 is rolling.

5 is a cross-sectional view just below the load when the load of the assembly of the safety pneumatic tire and the rim shown in FIG. 3 is rolling.

6 is a cross-sectional view of the assembly shown in FIG. 4 when the tire is punctured.

[Explanation of symbols]

Reference Signs List 1 safety pneumatic tire 2 pneumatic tire 3 tread part 3is tread inner surface 4 sidewall part 5 bead part 6 airbag 7 rim 8, 9 valve 10 reinforcing layer 11 bead core 12 radial carcass 13 belt 14 inner liner rubber E tire equator surface Sr flat road L load A air bladder maximum width position P ₁ tire internal pressure P ₂ air bladder pressure

Claims (17)

[Claims] 1. A safety pneumatic tire having a combination of a pneumatic tire including a tread portion, a pair of sidewall portions and a pair of bead portions connected to both sides thereof, and a tire tube-shaped air bag separately incorporated therein. In the tire, the pneumatic tire is provided with a reinforcing layer along the circumferential direction, the safety pneumatic tire is assembled to the rim, and the safety pneumatic tire is filled with a predetermined internal pressure separately for the pneumatic tire and the pneumatic tire. In the tread portion ground area in the rolling state of the load of the assembly of the tire and the rim, the airbag forms a gap between the reinforcing layer and the inner surface of the tread portion as an outer diameter growth suppressing member against centrifugal force. Having an outer peripheral surface to hold, with the above assembly,
When only the internal pressure of the pneumatic tire is zero as the gauge pressure, the reinforcing layer has a characteristic of extending by 15% or more in the circumferential direction thereof. 2. The safety pneumatic tire according to claim 1, wherein the airbag has one or more circumferentially continuous reinforcing layers on an outer peripheral portion thereof. 3. The safety pneumatic tire according to claim 1, wherein in the assembly, the airbag includes one or more circumferentially continuous reinforcing layers extending between its maximum width positions. 4. The pneumatic tire according to claim 1, wherein the airbag includes at least one circumferential continuous reinforcing layer on each of both side surfaces facing the pair of sidewall portions of the pneumatic tire. Safety pneumatic tire. 5. The safety pneumatic tire according to claim 1, wherein the airbag has an internal pressure equal to or higher than the internal pressure of the pneumatic tire. 6. When the internal pressure of the pneumatic tire in the assembly is only the gauge pressure of zero, the reinforcing layer is inscribed in the tread portion of the airbag in the tread portion grounding region of the assembly in a rolling state under load. The safety pneumatic tire according to any one of claims 1 to 5, which has an elongation characteristic that allows the elasticity to fall within the elastic limit. 7. The safety pneumatic tire according to claim 1, wherein the reinforcing layer has at least one layer of a composite of a fiber and a rubber composition. 8. The safety pneumatic tire according to claim 1, wherein the reinforcing layer is formed by laminating a composite layer of a fiber and a rubber composition in a range of 2 to 7 layers. . 9. The safety pneumatic tire according to claim 1, wherein the reinforcing layer has one or more resin layers. 10. The reinforcing layer has a thickness of 0.05 to 2.0 per layer.
mm, and one reinforcing layer has a maximum diameter within the range of 0.0001 to 0.2 mm and 8 in the rubber composition.
10. Fibers having a length of at least mm.
A safety pneumatic tire according to any one of the preceding claims. 11. The safety pneumatic tire according to claim 1, wherein the reinforcing layer contains 3 to 50% by mass of fibers in the rubber composition. 12. The safety air according to claim 1, wherein the reinforcing layer has a nonwoven fabric having a basis weight in a range of 10 to 300 g / m ^{2 in} the rubber composition. Containing tires. 13. A resin layer having a physical property of an initial elastic modulus in a range of 0.1 to 1.3 GPa, a yield stress in a range of 10 to 33 MPa, and an elongation at break of 20% or more. The safety pneumatic tire according to any one of claims 1 to 6, comprising: 14. When only the internal pressure of the pneumatic tire in the assembly is zero as the gauge pressure, the reinforcing layer is plastically deformed beyond the yield point in the tread contact area in the rolling state of the load of the assembly. The safety pneumatic tire according to any one of claims 1 to 5 and 13, which has a physical property that enables the tread portion of the airbag to be inscribed in a state. 15. The safety pneumatic tire according to claim 1, wherein the reinforcing layer is formed integrally with the airbag. 16. The safety pneumatic tire according to claim 1, wherein the reinforcing layer is formed separately from the airbag, and the airbag is joined to the reinforcing layer. 17. The reinforcing layer has a thickness of 0 to 5 in the tire circumferential direction.
% Elongation modulus at E (0-5) (kgf / cm), 5
The tensile modulus at 10% elongation is E (5-10) (kgf / cm)
Where E (0 to 5) / E (5 to 10) ≧ 2.0 and E (0 to 0)
5) The safety pneumatic tire according to any one of claims 1 to 16, wherein ≥ 5.0 (kgf / cm).