JP2002002221A - Pneumatic radial tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress or improve a deterioration caused by weight saving in various performance characteristics of a tire by eliminating a defect such as breaking or separation of a metal wire within a belt layer while using a no-twist metal wire as a reinforcing belt. SOLUTION: Rubber-covered belt plies 3 and 4 are taken as the bunches of the metal wires, wherein at least the bulk of the metal wires within the ply are put together in parallel without intertwisting the plural metal wires having approximately circular cross sections and approximately the same diameters, and the bunches of the metal wires are two-dimensionally disposed in parallel at an interval between the bunches in a width direction to constitute the belt layer. Rubber or a reinforcing layer 5 composed predominantly of the rubber is arranged between the belt layer and a tread.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic radial tire which is reduced in weight without impairing various performances of the tire, and more particularly to a pneumatic radial tire suitable as a radial tire for a passenger car.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for reducing the weight of tires in order to improve the fuel efficiency of automobiles. As a powerful means of weight reduction, a steel cord for reinforcing a belt has attracted attention, and a number of techniques for using the cord as a belt cord without twisting a metal wire have been disclosed. For example, JP-A-8-
Japanese Patent Application Laid-Open Nos. 218283 and 11-91311 disclose a technique of using a metal wire in a spiral shape or a waveform, and JP-A-4-19201 and JP-A-9-323503 disclose techniques relating to the use and arrangement of a single wire cord. Has been proposed,
In any case, there is a concern that the metal wire may be broken in severe use conditions or peeling may occur at the end of the belt. Also, JP-A-11-29
1710 describes a belt ply including a strand in which untwisted metal wires are aligned, but it is almost the same as a conventional twisted cord structure, and the effect of weight reduction cannot be expected much.

The applicant has previously proposed in Japanese Patent Application Laid-Open No. 4-95505 a technique for suppressing the growth and propagation of cracks generated at the belt end by a discrete arrangement of several monofilament bundles. Proposes a technique for improving belt durability by arranging into several monofilament bundles, and further arranging the filaments in the bundle to be further finely spaced apart from each other. A preferred driving density of the bundle is proposed. However, when the state is close to the state where the metal wires are arranged in a line in the width direction,
That is, when the degree of flatness of the metal wire bundle increases, belt rigidity decreases, belt breakage and belt layer peeling are likely to occur, and the problem that tire durability deteriorates remains unsolved. .

[0004]

Therefore, in order to respond to the need for further weight reduction of tires, we have used non-twisted metal wires as tire reinforcing belts and at the same time, bent the above-mentioned metal wires. Another object of the present invention is to solve problems in various tire properties such as peeling in a belt layer.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned disadvantages of the prior art and to minimize or improve the deterioration of various performances of a tire due to a reduction in weight. It is to provide radial tires.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and has a structure and a material of a tire reinforcing belt using a non-twisted metal wire, and a structure of an effective reinforcing layer. As a result of intensive research, the present invention has been completed.

That is, the pneumatic radial tire of the present invention
The present invention resides in each of the following inventions (1) to (21).

(1) A carcass layer composed of at least one radial carcass ply straddling in a toroidal manner between a pair of bead cores, and a carcass layer disposed outside the crown area of the carcass layer in the tire radial direction and grounded. Pneumatic radial tire, comprising: a tread forming a portion; and a belt layer including at least two belt plies made of a rubberized metal wire disposed between the tread and the crown region of the carcass layer. In at least one belt ply of the belt layer, a metal wire bundle in which at least most of the metal wires in the ply are aligned in parallel without twisting a plurality of metal wires having a circular cross section and substantially the same wire diameter The metal wire bundles are arranged in a plane in parallel with a space between the bundles in the width direction to form a belt layer, and the A pneumatic radial tire characterized by between de and the belt layer, at least one reinforcing layer composed mainly of rubber or rubber is disposed.

(2) The pneumatic radial tire according to the above (1), wherein the belt layer comprises two belt plies.

(3) All the belt plies of the belt layer are arranged in parallel without twisting a plurality of metal wires having at least most of the metal wires in the ply having a circular cross section and substantially the same wire diameter. The pneumatic radial tire according to the above (1) or (2), wherein the pneumatic radial tire exists as a metal wire bundle, and the metal wire bundles are arranged in a plane in parallel with an interval between the bundles in the width direction to form a belt layer. .

(4) The value of the ratio D _S / D _L of the short diameter D _S to the long diameter D _L of the metal wire bundle in a cross section orthogonal to the metal wire bundle is approximately 1 when the number of metal wires in the metal wire bundle is n. / P, the pneumatic radial tire according to any one of (1) to (3) above.

(5) The number n of metal wires in the metal wire bundle
The pneumatic radial tire according to any one of (1) to (4), wherein two to six tires are provided.

(6) The diameter of the metal wire in the belt layer is:
0.18-0.35 mm and its tensile strength is 3130
The pneumatic radial tire according to any one of the above (1) to (5), which has a pressure of up to 4410 MPa.

(7) The diameter of the metal wire in the belt layer is 0.19 to 0.28 mm, and its tensile strength is 3430.
The pneumatic radial tire according to any one of the above (1) to (5), which has a pressure of up to 4410 MPa.

(8) The material of the metal wire in the belt layer is
The pneumatic radial tire according to any one of the above (1) to (7), which is a steel material containing at least 0.7% by weight of carbon.

(9) The belt layer is composed of two belt plies, the total thickness of the two plies is G ₁ , and the distance between the metal wires of the radially inner ply and the outer ply is G _2. When the interval between the metal wire bundles in each ply is δG, the following equation is satisfied: 1.00 mm ≦ G ₁ ≦ 2.00 mm (1) 0.32 mm ≦ G ₂ ≦ 0.65 mm (2) 0.25 mm ≦ The pneumatic radial tire according to any one of the above (1) to (8), which satisfies δG ≦ 1.00 mm (3).

(10) The ratio of the reinforcing layer in the tire width direction is 7% of the width of the innermost belt ply in the tire radial direction.
The pneumatic radial tire according to any one of the above (1) to (9), which is in a range of 0 to 110%.

(11) The reinforcing layer has a thickness of 0.2 to 0.2.
Any one of the above (1) to (10), which is 1.2 mm
The pneumatic radial tire according to the item.

(12) The thickness of the reinforcing layer is from 0.3 to
Any one of the above (1) to (11) which is 0.8 mm
The pneumatic radial tire according to the item.

(13) 100% of the rubber portion of the reinforcing layer
The above (1) wherein the tensile stress is 1.0 to 8.0 MPa.
The pneumatic radial tire according to any one of (1) to (12).

(14) 100% of the rubber portion of the reinforcing layer
The pneumatic radial tire according to any one of the above (1) to (13), wherein a tensile stress is higher than a 100% tensile stress of the tread rubber.

(15) The pneumatic radial according to any one of the above (1) to (14), wherein the rubber-based reinforcing layer contains short fibers of organic fibers or metal fibers. tire.

(16) The above (1) to (1), wherein at least one cap layer formed by coating organic fibers with rubber is disposed between the belt layer and the tread.
The pneumatic radial tire according to any one of 5).

(17) From (1) to (1), at least one cap layer formed by rubber coating organic fibers is disposed between the reinforcing layer and the tread.
The pneumatic radial tire according to any one of 5).

(18) The above-mentioned (1), wherein the angle between the metal wire in the belt layer and the equatorial plane of the tire is 15 to 35 °.
The pneumatic radial tire according to any one of (1) to (17).

(19) The pneumatic radial tire according to any one of (1) to (18), wherein the organic fibers in the cap layer are arranged substantially parallel to a tire circumferential direction.

(20) The pneumatic radial tire according to any one of (1) to (19), wherein the organic fiber of the cap layer is polyethylene naphthalate.

(21) The pneumatic radial tire according to any one of (1) to (20), wherein the cord of the radial ply carcass is polyethylene naphthalate.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pneumatic radial tire according to one embodiment of the present invention will be specifically described with reference to FIGS.

The pneumatic radial tire of the present invention is shown in FIG.
An example is shown in the left half sectional view of FIG.
A carcass layer 2 composed of at least one radial carcass ply straddling in a toroidal shape therebetween, a tread 6 disposed outside the crown area of the carcass layer in the tire radial direction to form a ground contact portion, A belt layer comprising at least two belt plies (here, two of three and four) made of rubberized metal wires disposed between the tread and the crown region of the carcass layer. As shown in FIG. 2 or 3, at least one belt ply of the belt layer in the filled radial tire has at least a majority of metal wires in the ply having a circular cross section and a plurality of substantially the same wire diameters. The metal wires exist as metal wire bundles (three bundles in FIG. 2 and four bundles in FIG. 3) arranged in parallel without twisting the metal wires, and the metal wire bundles are spaced apart from each other in the width direction. A belt layer is constituted by being arranged in a row in a row, and at least one reinforcing layer 5 mainly composed of rubber or rubber is arranged between the tread and the belt layer. I do.

In general, the number of belt plies constituting the belt layer is selected in accordance with the load-bearing characteristics required of the tire, but the number of belt plies is usually selected. Two belt plies in which metal wires cross each other across the equator are preferably used.

In the conventional belt layer, a single metal wire separates the wires as shown in FIG. 4 or a twisted metal wire cord separates the cords as shown in FIG. Belt plies that are buried almost uniformly are often used. At least one belt ply of the belt layer of the present invention exists as a metal wire bundle in which a plurality of metal wires are aligned in parallel without being twisted, and the metal wire bundles are spaced apart from each other in the width direction. Are arranged in parallel and in a plane, and are embedded in the covering rubber. Due to the presence of the rubber portion at intervals between the bundles, the belt layer of the present invention has
The occurrence and propagation of peeling can be effectively suppressed.

In the present invention, all belt plies in the belt layer have at least a majority of the metal wires in the plies.
It exists as a metal wire bundle aligned in parallel as described above, and the metal wire bundle is arranged and arranged in a plane in parallel with an interval between the bundles in the width direction to form a belt layer. This is a preferred embodiment for improving the durability and reducing the weight of the tire.

[0034] In particular, more preferably 90% more than 80% of the total of the metal wire bundles, as shown in FIGS. 2 and 3, the ratio of the short diameter D _S to major D _L of the metal wire bundle in a cross section perpendicular to the metal wire bundle the value of D _S / D _L is approximately 1 / n preferably 1 / n
It is advantageous in implementation that the metal wire bundles are arranged in parallel in the width direction as a bundle aligned so that This short diameter / long diameter ratio D _S / D _L is 1 / n of 80
As the value deviates from 〜90% and increases, the thickness of the rubber for covering the metal wire bundle increases, so that the effect of achieving the reduction in the weight of the tire decreases. In this sense, the diameter of the metal wire as d, the value of at least minor D _S, 1.5 ×
It is desired that the value be equal to or less than the value of d.

The number of metal wires in the metal wire bundle of the present invention is preferably 2 to 6. There is no particular problem with the performance as a tire even if the number of metal wires in the bundle increases, but in the process of rolling the coated rubber on the metal wire cord, seven or more metal wires are aligned in parallel without twisting. As a bundle
It is difficult to arrange the bundles in the belt ply in a plane in parallel with an interval between the bundles in the width direction, and the productivity is reduced. Considering both the durability as a tire and the productivity as a member, the most advantageous number of metal wires in a bundle for implementation is 3 to 4.

The diameter of the metal wire used in the belt layer of the present invention is preferably 0.18 to 0.35 mm, more preferably 0.18 to 0.35 mm.
9 to 0.28 mm is more preferable. From the viewpoint of reducing the weight of the tire, the wire diameter should be reduced by reducing the wire diameter.However, if the wire diameter of the metal wire becomes too thin, a large number of wires must be driven to maintain the belt strength. The bundle interval becomes narrow, and the belt peeling resistance decreases. On the other hand, if the wire diameter of the metal wire is too large, the strain generated on the metal wire surface when the belt layer undergoes bending deformation increases, and when the tire undergoes large deformation such as sharp turning, the metal wire filament is It breaks easily.

The tensile strength of the metal wire of the present invention is 3130-4.
410 MPa is preferred, and 3430 to 4410 MP
a is more preferred. If the tensile strength is less than 3430 MPa, especially less than 3130 MPa, the amount of metal wire used must be increased in order to maintain the belt strength, and the weight of the tire cannot be reduced. For a metal wire having a tensile strength of more than 4410 MPa, difficulty in production increases and mass production becomes difficult.

For the belt layer of the present invention, a single metal wire (monofilament) which is not twisted is used. Conventionally used metal cords having a twisted structure of 1 × 3, 1 × 4, 1 × 5, etc., have reduced the strength by about 3% due to the loss caused by twisting. Therefore, there is an advantage that the initial tensile rigidity is particularly increased.

The material of the metal wire of the present invention is at least 0.1 mm.
It is desirable that the steel material contains 7% by weight of carbon, more preferably at least 0.8% by weight of carbon. A metal wire having a carbon content of less than 0.7% by weight has insufficient tensile strength as a tire belt reinforcing material. However, when the carbon content exceeds 0.9% by weight, it becomes difficult to draw a metal wire.

According to the present invention, there is provided a technique for reducing the weight of a tire by using a small amount of coated rubber and thinning a belt layer because the bundle of metal wires is arranged in a plane parallel to the width direction. Is possible.

When the belt layer of the present invention is composed of two belt plies, the total thickness of the two plies is G ₁ ,
When the space between the metal wires of the radially inner ply and the metal wire of the outer ply is G ₂ , and the space between the metal wire bundles in each ply is δG, the following equation is satisfied: 1.00 mm ≦ G ₁ ≦ 2.00 mm (1) It is preferable that 0.32 mm ≦ G ₂ ≦ 0.65 mm (2) 0.25 mm ≦ δG ≦ 1.00 mm (3). If G ₁ is less than 1.00 mm, the treat becomes weak, which makes the tire molding difficult. If it exceeds 2.00 mm, the thickness of the belt layer increases, which is not suitable for the purpose of reducing the weight. G ₂ is 0.32m
If it is less than m, the belt layer is easily deformed by the input to the tire tread and the belt durability is reduced. If it exceeds 0.65 mm, the advantage of weight reduction is unnecessary, and the advantage of weight reduction disappears. The rigidity is reduced, and the steering performance is reduced. If δG is less than 0.25, the occurrence and growth of the belt end separation cannot be suppressed. Penetration resistance (penetration) deteriorates.

The angle between the metal wire in the rubber-coated belt layer of the present invention and the equatorial plane of the tire is preferably 15 to 35 °. If the angle formed with the equatorial plane is less than 15 °, the durability is insufficient. If the angle exceeds 35 °, the rigidity in the circumferential direction of the belt decreases, which is not preferable as a radial tire.

In the pneumatic radial tire of the present invention, as shown in FIGS. 1 and 2, at least one reinforcing layer 5 mainly composed of rubber or rubber is disposed between the tread and the belt layer. It is characterized by having been done. Due to the arrangement of the reinforcing layer, when the tire runs at high speed or undergoes large deformation, sudden or excessive stress input from the tread surface to the belt layer is relaxed and absorbed, and the bundle arrangement of the metal single wire (monofilament) is reduced. Thus, the belt layer of the present invention is effectively protected without being damaged, cord breakage and cord peeling in the belt layer are suppressed, and tire durability is remarkably improved.

To improve the durability of the belt layer, the ratio of the rubber or the reinforcing layer mainly composed of rubber in the tire width direction is 70 to 11 times the innermost belt ply width in the tire radial direction.
The effect is most exhibited when it is within the range of 0%. If the ratio of the reinforcing layer in the tire width direction is less than 70% of the innermost belt ply width, there is a possibility that the occurrence of cord breakage and cord peeling particularly near the end of the belt layer may not be suppressed, and may exceed 110%. It is not necessary to occupy it, and there is a concern that the ride quality and road noise will deteriorate.

The thickness of the reinforcing layer is 0.2 to 1.2 mm
And more preferably 0.3 to 0.8 mm. If the thickness is less than 0.2 mm, the above-described protection suppressing effect is weak, and the occurrence of cord breakage and peeling may not be sufficiently suppressed. There is concern that comfort and road noise will be reduced.

The 100% tensile stress of the rubber portion of the reinforcing layer of the present invention is desirably 1.0 to 8.0 MPa. If it is less than 1.0 MPa, it is too soft to exert a sufficient reinforcing effect, and if it exceeds 8.0 MPa, it is too hard, so that the effect of absorbing and relaxing the input is reduced, and the ride comfort and feeling may be adversely affected. There is.

The rubber layer of the reinforcing layer according to the present invention has a thickness of 100%.
% Tensile stress is 100% of the tread rubber of the tire.
If it is higher than the tensile stress, and if it is lower than the tread rubber, the above-mentioned protective effect is weak, and the effect of absorbing and absorbing the input to the belt layer is weakened.

The reinforcing layer of the present invention has two types: a case where the above-mentioned required physical properties are imparted by the rubber composition; and a case where the required physical properties are imparted by filling the rubber composition as a main component with short fibers or the like.
There is a street.

In order to provide the above-mentioned preferable 100% tensile stress with a reinforcing layer made of a rubber composition, carbon black having a high reinforcing property, for example, SAF, ISAF, HAF,
It can be easily obtained by blending a relatively large amount of carbon black of a high reinforcing grade such as FEF, GPF, SRF or the like, preferably 40 to 80 parts by weight with respect to 100 parts of the rubber component.

In order to provide the reinforcing layer with the rubber composition as a main component and a reinforcing material to give required properties to the reinforcing layer, short fibers of organic fibers or metal fibers are added to the rubber composition.
A reinforcing layer mainly composed of rubber having the above physical properties can be easily obtained. The added short fibers are not particularly limited, and organic fibers generally used for tire reinforcement, such as polyester fibers, aliphatic polyamide fibers, aromatic polyamide fibers, rayon fibers and the like, and metal fibers such as steel fibers, Examples include stainless steel fibers. Among them, polyethylene terephthalate fiber, polyethylene naphthalate fiber, nylon 6 or nylon 66 fiber, aramid fiber, steel fiber and the like are preferably used. In addition,
In order to remarkably exhibit the reinforcing effect by adding these short fibers, the ratio L / d (aspect ratio) of the fiber length L to the fiber diameter d is desirably 3 to 100. When a reinforcing layer filled with short fibers, particularly short fibers having a large aspect ratio L / d, is used, it is important that the short fibers are oriented in the tire circumferential direction. This is useful for reinforcement and is desirable as an embodiment of the present invention.

In the present invention, at least one cap layer made of rubber coated with organic fibers may be disposed between the belt layer and the tread, particularly preferably between the reinforcing layer and the tread. Organic fibers in the cap layer are arranged substantially parallel to the tire circumferential direction,
This is advantageous in terms of steering stability and reduction of rolling resistance. As the organic fiber used for the cap layer, nylon fiber, polyethylene terephthalate fiber, polyethylene naphthalate fiber, rayon fiber, aramid fiber, etc. are preferably used. Particularly high, the present invention compensates for the lack of rigidity in the belt circumferential direction due to the use of a metal wire bundle having a relatively small diameter for weight reduction in the present invention, and can effectively reduce road noise. The cap layer is preferably wide enough to cover the entire width of the belt layer, but may be provided at both ends of the belt layer by being divided in the width direction of the belt layer.

As the cord of the radial carcass ply of the present invention, the same organic fiber as described above is used. In this case, polyethylene naphthalate fiber having a high elastic modulus may be used in place of the conventional nylon or polyester fiber. Advantageously, thereby significantly improving the handling stability and ride quality of the tire.

The metal wire in the belt layer of the present invention forms an angle of 15 to 35 ° with the equatorial plane of the tire, and the organic fibers in the cap layer are arranged substantially parallel to the tire circumferential direction. Is advantageous in implementation, whereby the rigidity in the circumferential direction of the belt is increased, and the steering performance and riding comfort are improved.

In the pneumatic radial tire according to the present invention, a plurality of metal monofilaments, which are bundled in a substantially planar manner without being twisted by several strands, are arranged in a belt ply in parallel and spaced apart from each other in a circumferential direction. Has achieved a lightweight belt layer with high rigidity and capable of suppressing the occurrence and propagation of peeling at the end of the belt, and with the provision of rubber or a reinforcing layer mainly composed of rubber, low rolling resistance and improved durability have been achieved. High-performance lightweight radial tires.

[0055]

Embodiments of the present invention will be described below with reference to the drawings and tables.

In the present embodiment, a belt layer composed of two belt plies having the specifications shown in the upper part of Table 1 and a rubber reinforcing layer having the specifications shown in the middle part of Table 1 were combined with the sectional structure shown in FIG. Is applied to a radial tire of size 175 / 70R14.

In Examples 1 to 3, the wire diameter was 0.30φ each,
As shown in FIG. 2, the metal wires of 0.21φ and 0.26φ are bundled every three wires and aligned in the width direction and embedded in the covering rubber. The width of the rubber reinforcing layer is 100, 80, and 100% with respect to the width of the first belt ply, respectively.

In each of the comparative examples, the rubber ply was not provided, the belt ply of the comparative example 2 was the same as that of the example 1, and the belt ply of the comparative example 1 was a three-ply cord shown in FIG.

[0059]

[Table 1]

With respect to each of the tires of the examples and the comparative examples, a belt break resistance test and a belt peel resistance test of the belt layer were performed, and the results are shown in the lower part of Table 1.

As shown by the results of Examples 1 to 3, the pneumatic radial tire according to the present invention in which a rubber reinforcing layer is provided using a belt layer composed of a belt ply in which metal wires are arranged in a bundle. It turned out that it was a tire excellent in durability, in which the breakability and the belt peeling property were suppressed.

Although the above-described embodiment is an example in which the reinforcing layer made of the rubber composition is arranged, the reinforcing layer in which the rubber composition is the main component and which is filled with short fibers or the like is also used.
The same or better durability improvement effect can be seen, and when combined with the cap layer arrangement, the effect of improving circumferential rigidity and reducing tread input appears, further improving tire durability and running performance. Can be seen.

Hereinafter, the test method performed in this example will be described in detail.

<Belt Layer Peeling Test> The test tire was assembled on a regular rim, filled with an internal pressure of 1.5 kgf / cm ² , mounted on a test car, and allowed to travel on a general road for 60,000 km. Is dissected to measure the length of the cracks occurring in the belt layer. The reciprocal of the crack length of each test tire was calculated and is shown as an index with the value of the conventional tire being 100. The larger this index is, the better the belt peeling resistance is.

<Test for Belt Breaking Resistance> In this test, the test tire was mounted on an actual vehicle, and after traveling 20,000 km at a speed of 60 km / h on a curved road, the tire after the test was dissected and the belt was dissected. The reinforcing material (metal wire bundle or cord) in the layer was sampled, the number of broken reinforcing materials was examined, and the reciprocal thereof was indicated as an index with the conventional tire being 100. The larger the index is, the better the belt breaking resistance is.

[0066]

As described above, with the pneumatic tire according to the present invention, the disadvantages of the prior art have been eliminated, and the reduction in various performances of the tire due to the weight reduction has been minimized or improved. Thus, it has become possible to provide a lightweight pneumatic radial tire.

[Brief description of the drawings]

FIG. 1 is a left half sectional view of a pneumatic radial tire according to the present invention.

FIG. 2 is an example of a bundle of three metal wires according to the present invention.

FIG. 3 is an example of four bundles of metal wires according to the present invention.

FIG. 4 is an example of a conventional cord in which metal wires are arranged at equal intervals.

FIG. 5 is an example of a conventional cord in which metal wires are twisted into a 1 × 3 structure.

FIG. 6 shows two layers in which a three-wire bundle arrangement according to the present invention is covered with rubber, with their longitudinal sectional views superimposed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Bead core 2 Carrier layer 3 1st belt ply 4 2nd belt ply 5 Reinforcement layer 6 Tread G ₁ Total thickness (mm) of _two coated rubbers of belt ply G ₂ Distance between metal wires in two belt plies ( mm) δG Interval between metal wire bundles in the ply (mm) d Wire diameter of the metal wire (mm) R ₁ Rubber covering the first belt ply R ₂ Rubber covering the second belt ply

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D07B 1/06 D07B 1/06 A

Claims (21)

[Claims] 1. A carcass layer comprising at least one radial carcass ply straddling in a toroidal manner between a pair of bead cores, and a ground contact portion disposed outside a crown region of the carcass layer in a tire radial direction. And a belt layer comprising at least two belt plies made of a rubberized metal wire disposed between the tread and the crown region of the carcass layer. At least one belt ply of the belt layer is a metal wire bundle in which at least a majority of the metal wires in the ply are circular in cross section and are aligned in parallel without twisting a plurality of metal wires having substantially the same wire diameter. Exists, and the metal wire bundle is arranged in parallel and in a plane in parallel with an interval between the bundles in the width direction to constitute a belt layer, and the tread and Between the serial belt layer, the pneumatic radial tire characterized by at least one reinforcing layer composed mainly of rubber or rubber is disposed. 2. The pneumatic radial tire according to claim 1, wherein the belt layer is composed of two belt plies. 3. The method according to claim 1, wherein all belt plies of the belt layer are
At least most of the metal wires in the ply exist as a metal wire bundle that is circular in cross section and is aligned in parallel without twisting a plurality of metal wires having substantially the same wire diameter. 3. The pneumatic radial tire according to claim 1, wherein the belt layer is configured to be spaced apart and arranged in a plane in parallel. 4. A value of a ratio D _S / D _L of a minor diameter D _S to a major diameter D _L of a metal wire bundle in a cross section orthogonal to the metal wire bundle is:
The pneumatic radial tire according to any one of claims 1 to 3, wherein the number of metal wires in the metal wire bundle is n, which is approximately 1 / n. 5. The number n of metal wires in the metal wire bundle is 2
The pneumatic radial tire according to any one of claims 1 to 4, wherein the number is from six to six. 6. A metal wire in the belt layer having a diameter of 0.1 mm.
18 to 0.35 mm and its tensile strength is 3130 to 4
The pneumatic radial tire according to any one of claims 1 to 5, wherein the pressure is 410 MPa. 7. The metal wire in the belt layer has a wire diameter of 0.1.
9 to 0.28 mm, and its tensile strength is 3430 to 44
The pneumatic radial tire according to any one of claims 1 to 5, wherein the pressure is 10 MPa. 8. The pneumatic radial tire according to claim 1, wherein a material of the metal wire in the belt layer is a steel material containing at least 0.7% by weight of carbon. 9. The belt layer is composed of two belt plies, the total thickness of the two plies is G ₁ , the interval between the metal wires of the radially inner ply and the outer ply is G ₂ , when the .delta.G the interval between the metal wire bundles in each ply, the formula of relationship _{1.00mm ≦ G 1 ≦ 2.00mm (1} ) 0.32mm ≦ G 2 ≦ 0.65mm (2) 0.25mm ≦ δG The pneumatic radial tire according to any one of claims 1 to 8, which satisfies ≤ 1.00 mm (3). 10. The ratio of the reinforcing layer in the tire width direction to 70 to the width of the innermost belt ply in the tire radial direction.
The pneumatic radial tire according to any one of claims 1 to 9, which is within a range of 110%. 11. The reinforcing layer has a thickness of 0.2 to 1.2.
The pneumatic radial tire according to any one of claims 1 to 10, wherein the diameter is in mm. 12. The reinforcing layer has a thickness of 0.3 to 0.8.
The pneumatic radial tire according to any one of claims 1 to 11, wherein 13. The rubber part of the reinforcing layer having a 100% tensile stress of 1.0 to 8.0 MPa.
3. The pneumatic radial tire according to any one of 2. 14. The pneumatic radial tire according to claim 1, wherein a 100% tensile stress of a rubber portion of the reinforcing layer is higher than a 100% tensile stress of the tread rubber. 15. The pneumatic radial tire according to claim 1, wherein the reinforcing layer containing rubber as a main component contains a single fiber of an organic fiber or a metal fiber. 16. The pneumatic pump according to claim 1, wherein at least one cap layer formed by coating organic fibers with rubber is disposed between the belt layer and the tread. Radial tire. 17. Between the reinforcing layer and the tread,
The pneumatic radial tire according to any one of claims 1 to 15, wherein at least one cap layer formed by coating organic fibers with rubber is disposed. 18. The method according to claim 1, wherein an angle between the metal wire in the belt layer and an equatorial plane of the tire is 15 to 35 °.
7. The pneumatic radial tire according to any one of items 7 to 7. 19. The pneumatic radial tire according to claim 1, wherein the organic fibers in the cap layer are arranged substantially parallel to a tire circumferential direction. 20. The organic fiber of the cap layer,
The pneumatic radial tire according to any one of claims 1 to 19, wherein the pneumatic radial tire is polyethylene naphthalate. 21. The cord according to claim 1, wherein the cord of the radial ply carcass is polyethylene naphthalate.
The pneumatic radial tire according to any one of the above items.