JP2002160506A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire with a simplified structure and a high endurance for external damage, that is, resistance for external input, especially for avoiding a sharp foreign substance stuck in a tread from penetrating the inside of the tire. SOLUTION: In the pneumatic tire toroidally making a carcass 1 extending between a pair of beads a framework and provided with a tread 3 on the outside of the radial direction of the carcass 1, at least one reinforcing layer 4 arranging a reinforcing thin plate 40 continued between the carcass 1 and the tread 3 in the direction of at least tread width along the circumferential direction of the tread is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire that achieves safe running by avoiding air leakage due to external injury.

[0002]

2. Description of the Related Art In recent years, from the standpoint of environmental protection, it has been required to improve fuel efficiency of automobiles. Therefore, automobile manufacturers are conducting research on vehicles powered by fuel cells, while tire manufacturers are aiming to reduce the rolling resistance of tires by, for example, applying fuel containing silica to the tread to reduce fuel consumption. Research and development of tires are being conducted. Further, from the viewpoint of reducing the weight of automobiles, which is closely related to actual fuel efficiency, there is a strong demand from automobile manufacturers for weight reduction of tires.

Further, as another measure for reducing the weight of the automobile, studies have been made to reduce the weight of the spare tire by omitting the mounting of the spare tire on the vehicle. To do so, the vehicle must have a reduced internal pressure due to trauma,
In other words, when a puncture occurs, the minimum necessary distance,
For example, it is necessary to mount a so-called run-flat tire which enables safe driving of a distance to a facility capable of repairing and replacing a tire. Therefore, development of this run flat tire has been promoted with a passenger car tire in mind.

[0004] By the way, the puncture phenomenon is roughly classified into two types. One of them is that as a result of severe damage to the tire,
This is a phenomenon called a burst, in which air suddenly escapes from the inside of the tire. The other one is the so-called slow puncture, in which nails and screws penetrate the tread of the tire and reach the inside of the tire, and the air inside the tire gradually escapes through this penetration path, causing a gradual decrease in internal pressure. This is a phenomenon called char.

[0005] The slow puncture phenomenon is difficult to recognize from the appearance of the tire because the internal pressure of the tire gradually decreases. In order for the driver to recognize that such a phenomenon has occurred and avoid danger, for example, it is possible to install an internal pressure alarm device and issue an alarm to the driver when the internal pressure drops, but it is possible to deal with it. Since the mounting increases the weight of the vehicle, it is incompatible with the above-mentioned reduction in the weight of the vehicle, and has a disadvantage of increasing the cost. Therefore, it is important to provide the tire itself with an ability to avoid a puncture phenomenon due to penetration of nails or screws.

A pneumatic tire has a structure in which at least three layers of belts and treads are sequentially arranged radially outside a carcass extending in a toroidal shape between a pair of bead parts, particularly in a truck and bus tire.
In order to prevent external input from road surface protrusions etc. from penetrating the tread rubber and further reaching the inside of the tire from the belt and carcass, a belt made of rubberized cloth of cords arranged in parallel is arranged. are doing. That is, the belt is composed of at least three layers in which a rubberized material in which a number of cords made of steel or organic fibers are covered with rubber is laminated, and the cords constituting each belt layer are arranged to intersect between adjacent belt layers. It is common to include a so-called cross belt layer. Due to the mesh structure of the cords in the cross belt layer, an external input from the tread surface is received by the belt, and is prevented from reaching the inside of the tire.

However, when a relatively small-diameter sharp object such as a nail or a screw is stabbed on the tread tread, if the diameter is smaller than the mesh of the cord of the belt, the belt penetrates the belt, and in that state, the traveling is further repeated. As a result, foreign matter reaches the inside of the tire through the carcass, and a passage for air leakage is formed, thereby causing a slow puncture phenomenon.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a simplified and highly durable against external injury, in particular, to prevent sharp foreign objects stuck in a tread from penetrating into the tire, and to prevent external input. An object of the present invention is to provide a pneumatic tire having a simplified structure.

[0009]

The gist of the present invention is as follows.
It is as follows. (1) In a pneumatic tire having a carcass extending in a toroidal shape between a pair of bead portions and having a tread radially outside of the carcass, the pneumatic tire is continuous between the carcass and the tread at least in the tread width direction. A pneumatic tire having at least one reinforcing layer in which a reinforcing thin plate is arranged along a tread circumferential direction.

(2) The pneumatic tire according to the above (1), wherein the reinforcing layer is made of a reinforcing thin plate continuous in the circumferential direction of the tread.

(3) The pneumatic tire according to (1), wherein the reinforcing layer is formed by arranging a plurality of thin reinforcing plates in the circumferential direction of the tread.

(4) The pneumatic pump according to (3), wherein the reinforcing layers are arranged side by side in the circumferential direction of the tread without gaps in an arrangement in which adjacent reinforcing thin plates at least partially overlap. tire.

(5) The pneumatic tire according to the above (4), wherein an elastic adhesive layer is interposed between the adjacent reinforcing thin plates.

(6) In the above (4) or (5), the length in the tread circumferential direction of the overlapping portion between adjacent reinforcing thin plates is 10 to 80% of the length in the tread circumferential direction of the reinforcing thin plates. A pneumatic tire characterized by the following.

(7) The pneumatic tire according to any one of the above (1) to (6), wherein the reinforcing thin plate is made of a polymer compound.

(8) The pneumatic tire according to any one of the above (1) to (6), wherein the reinforcing thin plate is made of metal.

(9) The pneumatic tire according to any one of the above (1) to (8), wherein the length of the reinforcing thin plate in the circumferential direction of the tread is 3 mm or more.

(10) The pneumatic tire according to any one of the above (1) to (9), wherein the thickness of the reinforcing thin plate is 0.05 to 1.5 mm.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific structure of the present invention will be described by taking a pneumatic radial tire for trucks and buses shown in FIG. 1 as an example. In addition, the pneumatic tire shown in FIG. 1 is arranged in a carcass 1 made of, for example, a ply of a steel cord, which extends in a toroidal shape in a radial direction between a pair of bead portions, and is disposed outside a crown portion of the carcass 1 in a tire radial direction. In the illustrated example, the belt 2 has substantially two layers of belts 2 and a tread 3 disposed radially outward of the belt 2, and at least one layer is provided between the belt 2 and the tread 3.
In the illustrated example, two reinforcing layers 4 are arranged.

The reinforcing layer 4 is formed by arranging at least a reinforcing thin plate 40 continuous in the tread width direction along the tread circumferential direction. More specifically, the reinforcing layer 4 is continuous in the tread width direction and has a tread circumferential direction. The reinforcing layer 4 is formed by arranging at least one reinforcing thin plate 40 extending in the direction along the circumferential direction of the tread.

In the reinforcing layer 4 thus obtained, the outer surface in the tire radial direction of the belt 2 is entirely covered with the reinforcing thin plate 40. Therefore, even when there is a projection input from the tread surface of the tread 3, for example, when the nail 5 shown in FIG. 1 penetrates the tread 3, the nail 5 is prevented from proceeding into the tire by the reinforcing thin plate 40. As a result, the trauma does not extend to the inside of the tire.

The reinforcing thin plate 40 has a thickness t of 0.05
It is preferable to set it to 1.5 mm. Because the reinforcement sheet 40
If the thickness t is less than 0.05 mm, the penetration of nails and the like may be insufficiently prevented. On the other hand, if the thickness t exceeds 1.5 mm, the bending stiffness becomes too high, and the reinforcing thin plate may 40 may not bend smoothly.

Further, the width W of the reinforcing layer 4 is preferably 45 to 120% of the tread tread width TW. That is, if the width W is less than 45% of the width TW, the penetration of nails or the like may be insufficiently prevented. On the other hand, if the width W is more than 120% of the width TW, the tire is most bent at the load-loaded rolling ground of the tire. Large deformation,
Since the reinforcing thin plate 40 extends to the tire shoulder region, stress deformation is concentrated on the end of the reinforcing thin plate due to the bending deformation, and a crack may be generated from the end of the reinforcing thin plate.

The reinforcing layer 4 is not a reinforcing thin plate 40 continuous in the tread circumferential direction, but a plurality of reinforcing thin plates 40 having a short length in the tread circumferential direction are arranged in parallel in the tread circumferential direction. 4 may be configured. In this case, as shown in FIG. 2, the reinforcing layer 4 has a substantially two-layer structure.

That is, as shown in FIG. 3, the reinforcing layer 4 has a width extending over the entire width of the tread as shown in FIG. A layer 4a in which a plurality of reinforcing thin plates 40a having a length in the tread circumferential direction shorter than this width are arranged in parallel at equal intervals in the tread circumferential direction, and a layer 4a And a layer 4b in which a plurality of reinforcing thin plates 40b slightly narrower than the reinforcing thin plate 40a are arranged at equal intervals in the tread circumferential direction. This reinforcing layer 4 is shown in FIG.
As shown in (c), the gap 41a between the reinforcing thin plates 40a in the tire radially inner layer 4a of the reinforcing layer 4 does not overlap with the gap 41b between the reinforcing thin plates 40b in the tire radially outer layer 4b. It is important to arrange them.

The reinforcing layer 4 thus obtained is closed by one of the reinforcing thin plates 40a and 40b without the gaps 41a and 41b between the reinforcing thin plates communicating with each other in the tire radial direction. The outer side surface is completely covered by the reinforcing thin plates 40a and 40b. Therefore, even if the nail 5 shown in FIG. 1 penetrates the tread 3, for example, the nail 5 is prevented from proceeding into the tire by the reinforcing thin plates 40a and 40b. Is avoided.

Here, when forming the reinforcing layer 4 by arranging a plurality of reinforcing thin plates in parallel, it is preferable that the width x of the gap between the reinforcing thin plates 40a or 40b is 0.3 mm or more. This is because if the width x is less than 0.3 mm, the coating layer of rubber or the like may not sufficiently enter the gap between the reinforcing thin plates 40, and the adhesion between the reinforcing thin plate and the coating rubber may not be sufficiently secured. is there.

Further, when the reinforcing layer 4 has a laminated structure of two or more layers, the gap between the layers, for example, the gap h between the layers 4a and 4b shown in FIG. preferable. If the gap h is less than 0.1 mm, the gap between the reinforcing layers 4a and 4b disappears mainly due to manufacturing variations, and a portion where the reinforcing layers 4a and 4b do not adhere to the covering rubber occurs. If the thickness exceeds 1.0 mm, the weight increases, which results in a contradiction to the weight reduction of the tire described above.

Further, in forming the reinforcing layer 4 with a plurality of reinforcing thin plates, as shown in FIG. 4, a reinforcing thin plate 40a having a width substantially covering the entire width of the tread and a reinforcing thin plate 40b having a width smaller than this width are formed by: Partially overlapped and arranged alternately in the tread circumferential direction. As described above, the reinforcing layer 4 in which the reinforcing thin plates 40a and 40b are partially overlapped with each other also has the tire 2 radially outer surface of the belt 2 entirely covered with the reinforcing thin plates 40a and 40b. Therefore, for example, even when the nail 5 shown in FIG. 1 penetrates the tread 3, the nail 5 is prevented from progressing into the tire by the reinforcing thin plates 40a and 40b, and as a result, the trauma extends to the inside of the tire. Spreading is avoided.

Here, as shown in FIG. 4C, the length l in the tread circumferential direction (hereinafter referred to as overlap length) of the overlapping portion between adjacent reinforcing thin plates 40a and 40b is determined by the tread circumferential length of the reinforcing thin plate. It is preferably 10 to 80% of the length L in the direction. Because, when the overlap length l is less than 10% of the length L,
There is a concern that the overlapping of the reinforcing thin plates 40a and 40b is not sufficient and the overlapping portion becomes zero due to manufacturing variations.
On the other hand, when the ratio exceeds 80%, the number of reinforcing thin plates 40a and 40b increases, resulting in an increase in weight.

An elastic adhesive layer such as rubber or ultra-high molecular weight polyethylene is interposed at least in the gap h between the reinforcing thin plates shown in FIGS. It is preferable to secure the elastic adhesive fixation. That is, when a strain input such as bending deformation occurs in the reinforcing thin plate during rolling of the tire under load, it is possible to avoid concentration of stress and strain at the end of the reinforcing thin plate.

Here, for the reinforcing thin plate constituting the reinforcing layer 4, it is preferable to use a material having flexibility and excellent penetration resistance (cut resistance), for example, a polymer compound, metal and nonwoven fabric. . That is, a polymer compound such as an epoxy resin, polyethylene terephthalate (PE
T), when a film such as polyethylene naphthalate (PEN) or polyethylene is used as the reinforcing thin plate 5, for example, the composite material is mixed via an adhesive made of a mixture of an organic compound diluted with toluene or the like and a mineral filler. 4 to the surface. Similarly, when the nonwoven fabric is used as the reinforcing thin plate 5, it is bonded to the surface of the composite material 4 using the above-mentioned adhesive.

Further, metals such as steel and copper alloy (brass)
When a thin plate such as the above is used as a reinforcing thin plate, the steel plate is plated with brass, and the copper alloy is left as it is, and the metal plate can be joined to the tread and the belt side rubber by performing vulcanization. Note that a metal such as stainless steel which is difficult to be plated is preferably bonded to rubber via an adhesive used for the above-described polymer compound.

When the reinforcing thin plate 40 is arranged adjacent to the carcass, and particularly made of a polymer compound or metal, the reinforcing thin plate prevents air from flowing into and out of the tire in the tire crown portion. Therefore, it becomes possible to omit the inner liner disposed on the inner peripheral wall of the tire in the crown portion in order to prevent the transmission of air,
The weight of the tire is reduced.

Further, the reinforcement of the surface with the reinforcing thin plate is effective to increase the rigidity in the belt width direction and the rigidity against bending and shear deformation along the belt surface, which cannot be obtained by the conventional cord reinforcement. Since the belt strength achieved by using three or more belts is secured by two or less (partially one), the number of belts can be reduced. In particular, when a reinforcing layer is constituted by a plurality of reinforcing thin plates, if a corrugated cord as shown in FIG. 3 is used for the reinforcing cords constituting the belt, the belt can be partially partially combined with the reinforcing thin plates. It can be a layer.

[0036]

EXAMPLE 1 A radial tire for trucks and buses of size 435/45 R22.5 shown in FIG. 2 was reinforced with a reinforcing layer A having the following specifications.
~ D was applied. The specifications of the belt are also described in combination with the above-mentioned reinforcing layers A to D. For comparison, a conventional tire having the belt E shown below and having no reinforcing layer was also experimentally manufactured.

Each of the tires thus obtained was mounted on a standard rim, and as shown in FIGS. 1 and 2, a diameter of 3 mm and a length of 15 mm were measured from the tread 3 to the nearest to the reinforcing layer 4 (the conventional tire was immediately near the belt). Hammer in the nail
Next, while the tire internal pressure was adjusted to 900 kPa and a load of 54 kN was applied, the drum was run at 60 km / h, and the running distance until the tire internal pressure was reduced to half was measured. as a result,
While the internal pressure of the conventional tire was reduced by half after traveling for 2000 km, the internal pressure of the inventive tire having the reinforcing layers A to D was not observed even after traveling for 10,000 km. Further, the nails that have been driven have penetrated from the belt to the inside of the inner liner layer in the conventional tire, but none of the nails reached the belt in the inventive tire.

[Reinforcing layer A] As a reinforcing thin plate, thickness t: 0.2 mm, width W: 35
Using a normal steel plate having a thickness of 0 mm and a length L of 20 mm, the reinforcing thin plates were arranged in the circumferential direction of the tread with an interval width x: 2 mm as shown in FIG. A layer in which reinforcing thin plates are arranged is laminated with an interlayer gap h of 0.3 mm. Note that an elastic adhesive layer made of rubber was interposed in the interlayer gap h. The belt to be combined with the reinforcing layer A is 3
+ 9 + 15 × 0.19mmφ steel cord with 27.5 shots
It is composed of two layers of layers wound spirally around the outer periphery of the carcass crown portion along the circumferential direction so as to be 50/50 mm.

[Reinforcing layer B] The reinforcing layer B has the same structure as the reinforcing layer A, and the belt combined with the reinforcing layer B is 1 + 6 × 0.34 mmφ.
Of the carcass crown portion is spirally wound around the outer periphery of the carcass crown portion in the circumferential direction so that the number of steel cords to be driven is 27.5 / 50 mm.

[Reinforcing layer C] Thickness t: 0.2 m as a reinforcing thin plate
m, a width W: 350 mm, and a length L: 20 mm, using a normal steel plate, and forming the reinforcing thin plate in such a manner that an 8 mm long portion (l in FIG. 4) between adjacent reinforcing thin plates is formed as shown in FIG. Interlayer gap h: It is arranged in parallel in the circumferential direction of the tread by being overlapped with a gap of 0.3 mm. Note that an elastic adhesive layer made of rubber was interposed in the interlayer gap h at the overlapped portion. The structure of the belt combined with the reinforcing layer C is the same as that of the reinforcing layer B.

[Reinforcing Layer D] The reinforcing layer A has the same structure as the reinforcing layer A, and the structure of the belt combined with the reinforcing layer D is the same as that of the reinforcing layer B.

[Belt E] 2 layers of a layer obtained by spirally winding a steel cord of 1 + 6 × 0.34 mmφ around the outer periphery of the carcass crown portion along the circumferential direction so as to have a driving number of 27.5 cords / 50 mm; 1 + 6 on the radial outside of these two layers
× 0.34mmφ steel cord 45 with respect to the tire equatorial plane
And 24 layers / 50 mm arranged at an inclination angle of °.

Example 2 Reinforcing layers F and G having the following specifications were applied to radial tires for passenger cars of size 195/65 R14. The specifications of the belt are also described in combination with the reinforcing layers F and G. For comparison, a conventional tire having a belt H shown below and having no reinforcing layer was also experimentally manufactured.

Each of the tires thus obtained was mounted on a standard rim, and as shown in FIGS. 1 and 2, a diameter of 3 mm and a length of 10 mm were measured from the tread 3 to the nearest to the reinforcing layer 4 (the conventional tire was immediately near the belt). Hammer in the nail
Next, while the tire internal pressure was adjusted to 200 kPa and a load of 5.5 kN was applied, the drum was run at 80 km / h, and the running distance until the tire internal pressure was reduced to half was measured. as a result,
While the internal pressure of the conventional tire was reduced by half after traveling for 300 km, the internal pressure of the invention tire having the reinforcing layer F or G did not decrease even after traveling for 10,000 km. Further, the nails that have been driven have penetrated from the belt to the inside of the inner liner layer in the conventional tire, but none of the nails reached the belt in the inventive tire.

[Reinforcing layer F] As a reinforcing thin plate, thickness t: 0.1 mm, width W: 14
Using a normal steel plate having a thickness of 0 mm and a length L of 20 mm, the reinforcing thin plates were arranged in the circumferential direction of the tread with an interval width x: 2 mm as shown in FIG. A layer in which reinforcing thin plates are arranged is laminated with an interlayer gap h of 0.3 mm. Note that an elastic adhesive layer made of rubber was interposed in the interlayer gap h. The belt to be combined with the reinforcing layer F is a layer in which a polyethylene naphthalate cord (1500 d / 2) is helically wound around the outer periphery of the carcass crown portion along the circumferential direction so as to have a number of 50/50 mm. Consisting of two layers.

[Reinforcing layer G] As reinforcing thin plate, thickness t: 1.5 m
Using a polyethylene naphthalate film having an m and a width W of 140 mm, the reinforcing thin plate is formed as a continuous layer in the circumferential direction of the tread as shown in FIG. The belt to be combined with the reinforcing layer G is made of a polyethylene naphthalate cord (1500d / 2), and is driven into a number of 50/50.
The carcass crown is composed of two layers spirally wound around the outer periphery of the carcass crown portion along the circumferential direction so as to have a diameter of mm.

[Belt H] A layer 2 of a layer obtained by spirally winding a polyethylene naphthalate cord (1500 d / 2) around the outer periphery of the carcass crown portion along the circumferential direction so that the number is 50/50 mm. Composed of a layer and a layer in which 1 + 3 × 0.30 mmφ steel cords are arranged at an inclination angle of 45 ° with respect to the tire equatorial plane at a number of 30/50 mm on the radially outer side of the two layers. .

[0048]

According to the present invention, it is possible to provide a pneumatic tire having a simplified structure having a high durability against damage and avoiding a sharp foreign matter stuck in the tread from penetrating into the tire.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view in the width direction of a tire according to the present invention.

FIG. 2 is a cross-sectional view in the width direction of the tire of the present invention.

FIG. 3 is a diagram showing a structure of a reinforcing layer according to the present invention.

FIG. 4 is a diagram showing a structure of a reinforcing layer according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carcass 2 Belt 3 Tread 4 Reinforcement layer 40 Reinforcement thin plate 40a Reinforcement thin plate 40b Reinforcement thin plate

Claims (10)

[Claims] 1. A pneumatic tire having a carcass extending in a toroidal shape between a pair of bead portions and having a tread radially outside of the carcass, a pneumatic tire having a carcass and a tread at least in a tread width direction. A pneumatic tire having at least one reinforcing layer in which continuous reinforcing thin plates are arranged along a tread circumferential direction. 2. The pneumatic tire according to claim 1, wherein the reinforcing layer is formed of a reinforcing thin plate that is continuous in a tread circumferential direction. 3. The pneumatic tire according to claim 1, wherein the reinforcing layer is formed by arranging a plurality of thin reinforcing plates in a circumferential direction of the tread. 4. The pneumatic tire according to claim 3, wherein the reinforcing layers are arranged in such a manner that adjacent reinforcing thin plates at least partially overlap with each other and the reinforcing thin plates are arranged side by side in the tread circumferential direction without gaps. 5. The pneumatic tire according to claim 4, wherein an elastic adhesive layer is interposed between adjacent reinforcing thin plates. 6. The tread circumferential length of the overlapping portion between adjacent reinforcing thin plates is 10 to 80% of the tread circumferential length of the reinforcing thin plates according to claim 4 or 5. Pneumatic tire. 7. The method according to claim 1, wherein
A pneumatic tire, wherein the reinforcing thin plate is made of a polymer compound. 8. The method according to claim 1, wherein
A pneumatic tire, wherein the reinforcing thin plate is made of metal. 9. The method according to claim 1, wherein
A pneumatic tire, wherein the length of the reinforcing thin plate in the circumferential direction of the tread is 3 mm or more. 10. The pneumatic tire according to claim 1, wherein the thickness of the reinforcing thin plate is 0.05 to 1.5 mm.