JPH07304307A - Reinforced core for tire and pneumatic tire using it - Google Patents

Abstract

PURPOSE:To lessen the thickness of a cord while ensuring necessary bending rigidity and compression rigidity to help lightening a tire. CONSTITUTION:In this reinforced cord 10, 2-6 steel-made filaments 13 are arranged laterally in the same plane without adding lay to be aligned in parallel, are made into a belt state wherein respective adjoining filaments 13 and 13 adhere intermittently, and moreover the diameters D of the respective filaments 13 are made in a range of 0.15-0.3mm. In this pneumatic tire, reinforced plies 7A and 7B using this reinforced cord and having a thickness of 1mm or less are arranged on the outer side in the radius direction of a carcass 6.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention can reduce the thickness of the cord while ensuring the required bending rigidity and compression rigidity.
TECHNICAL FIELD The present invention relates to a reinforcing cord for a tire, which is useful for weight reduction, and a pneumatic tire using the same.

[0002]

2. Description of the Related Art Pneumatic tires having a radial structure in which a tread portion is reinforced with a tough belt layer have been widely used as the speed and performance of vehicles have increased. The cord is usually made by twisting multiple steel filaments together, eg 1x3, 1x
A so-called steel cord having a four-structure or the like is widely used.

However, in recent years, in order to improve the fuel efficiency performance and the exercise performance of vehicles, it has been strongly desired to reduce the weight of tires.
In particular, in the belt layer, which accounts for a relatively large proportion of the weight of the tire, a non-metallic material such as an aromatic polyamide fiber having a small specific gravity is used instead of the steel cord.

[0004]

However, the cord using the non-metallic material has a problem that the bending rigidity and the compression rigidity are insufficient, and the steering stability, wear resistance, noise characteristics, etc. are deteriorated.

In European Patent Publication No. 492682, as shown in FIG. 5, two to seven steel core filaments F1 made parallel to each other in the same plane are aligned.
There is proposed a flat strip-shaped cord obtained by bundling the above with a wrapping filament F2.

Although this one can reduce the thickness of the cord and reduce the weight of the tire, since it is bundled by the wrapping filament, the contact pressure acts between the adjacent filaments, and as a result, the filaments are deformed when the tire is deformed. Inferior in durability such as inducing abrasion damage. Also, since each filament is arranged independently, the bending rigidity of the cord does not greatly exceed the sum of the bending rigidity of the filaments.
There is also a problem that the bending rigidity is insufficient and the cord weight and cord thickness are unnecessarily increased by the wrapping filament.

The present invention is based on intermittently adhering filaments that are aligned parallel to each other in the same plane, and achieves high bending rigidity and compression rigidity while greatly reducing the thickness of the cord. And a pneumatic tire using the same.

[0008]

In order to achieve the above object, the first invention of the present application is to arrange 2 to 6 steel filaments in parallel in the same plane without twisting them. The filaments that are aligned and adjacent to each other are bonded intermittently, and the diameter of each filament is set to 0.1.
A reinforcing cord for a tire having a range of 5 to 0.3 mm.

A second aspect of the present invention is a carcass which is folded back around the bead core of the bead part from the tread part to the side wall part, and a reinforcing cord which is arranged radially outside the carcass and inside the tread part. The reinforcing cord is provided with at least one reinforcing ply embedded in rubber, and the reinforcing cord has two to six steel filaments arranged in parallel in the same plane without twisting. A pneumatic tire in which filaments aligned and adjacent to each other are intermittently adhered to each other to form a belt shape, and the diameter of each filament is in the range of 0.15 to 0.3 mm and the thickness of the reinforcing ply is 1 mm or less.

[0010]

The reinforcing cord is formed of filaments that are aligned in parallel with each other in the same plane. Therefore, the thickness of the cord can be reduced to be equal to the diameter of the filament, and the ply thickness can be maintained at 1 mm or less even when the filament having the diameter D of 0.15 to 0.3 mm is used. Therefore, it is possible to significantly reduce the weight of the tire.

Further, since the adjacent filaments are intermittently adhered to each other, the filaments can be restrained from each other, and the bending rigidity can be greatly improved while maintaining the characteristics such as tensile elasticity as a cord. Is possible.

Further, since the filaments are intermittently bonded by adhesion, no contact pressure acts between the filaments, abrasion damage of the filaments during bending deformation can be reduced, and the durability of the cord can be greatly enhanced. It is also possible to provide a minute gap between the filaments, at which time the durability of the cord is further improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the figure, a pneumatic tire 1 has a tread portion 2,
The sidewall portion 3 extends inward in the tire radial direction from both ends of the tread portion 2, and the bead portion 4 located at the tire radial inner end of each sidewall portion 3 is provided. A flat radial tire having a flatness ratio of 80% or less, for example 65%, is formed.

Further, the pneumatic tire 1 has the bead portion 4,
A carcass 6 whose both ends are folded back around the bead core 5 of the bead part 4 from the tread part 2 to the sidewall part 3 is bridged between the four, and the carcass 6 is radially outward of the carcass 6 and inside the tread part 2. A tough reinforcing layer 7 is wound around.

The carcass 6 has at least one carcass cord arranged at an angle of 75 to 90 degrees with respect to the tire equator.
The carcass ply 6A is composed of a sheet of carcass, and between the toroidal body portion 6a of the carcass 6 and the folded-back portions 6b at both ends thereof, a hard taper extending from the bead core 5 outward in the tire radial direction. A bead apex 8 is provided to reinforce from the bead portion 4 to the sidewall portion 3 and enhance the tire lateral rigidity.

In this example, the carcass 6 is formed of, for example, one carcass ply 6A using polyester fiber, but as the carcass cord, other organic fiber cords such as nylon, rayon and aromatic polyamide are suitable. Ordinary metal cords, which can be used and in which steel filaments and the like are twisted together, can be adopted depending on the required tire performance.

The reinforcing layer 7 is a so-called belt layer formed of at least one reinforcing ply 7A placed inside the carcass 6 in this example and an outer reinforcing ply 7B placed outside thereof. Therefore, the tread portion 2 is reinforced substantially over its entire width with a hoop effect.

Each reinforcing ply 7A, 7B is a reinforcing cord 1.
A cord array 11 in which 0s are arrayed at an angle of 10 to 30 degrees with respect to the tire equator is embedded in a tread rubber 12 to form a sheet shape. In this example, the reinforcement plies 7A and 7B have reinforcement cords 10 between the plies. They are arranged in opposite directions so that they intersect at.

As shown in FIGS. 2 and 3, the reinforcing cord 10 has 2 to 6 filaments 13 made of steel and having a diameter D of 0.15 to 0.3 mm without twisting, that is, without. It is formed into a flat band shape in which twisted filaments are arranged side by side in the same plane and aligned in parallel with each other, and adjacent filaments 13 are intermittently bonded. As a result, the reinforcing plies 7A and 7B have a thickness t of 1.0 mm or less,
It is preferably set to 0.8 mm or less.

In the present embodiment, the reinforcing cords 10 are composed of four filaments 13, and the filaments 13 are arranged in parallel with each other with a minute interval d and are bonded by using a welding means such as spot welding. To be done. In addition, as an adhesive, an adhesive means using, for example, a thermosetting adhesive, an alloy adhesive, or the like can be adopted.

As described above, since the reinforcing cords 10 bond the filaments 13 to each other by adhesion, the restraining force acts between the filaments, and the bending rigidity is greatly improved.

The pitch length of the intermittent bonding, that is, the pitch length L of the bonding portion K between the filaments 13 is L.
Is preferably 30 to 70 times the diameter D of the filament 13, and the bonding length KL of each bonding portion K is preferably 2 times or less the diameter D. When the pitch length is less than 30D and the bonding length KL is greater than 2D, the characteristics as a cord cannot be expected, and conversely, when the pitch length L exceeds 70D, the effect of improving bending rigidity is unsatisfactory. Will be enough. In addition, as shown in FIG. 4, in the bonding, the bonded portion K between the adjacent filaments on one side and the bonded portion K between the adjacent filaments on the other side are displaced in the axial direction, and the bonded portion K is moved. However, from the viewpoint of maintaining the characteristics as a cord, the adhesive portion K is
As shown in FIG. 3, it is preferable to form them side by side.

The distance d between the filaments 13 is preferably 0.2 to 0.3 times the diameter D. When the distance d is less than 0.2D, the filaments 13 are deformed when the tire is deformed. They tend to contact each other and cause abrasion, resulting in reduced durability. On the contrary, when the distance d is larger than 0.3D, the cord width becomes excessively large, and the ply number needs to be increased such that the filament driving number E described later becomes insufficient, which hinders weight reduction.

The reinforcing cord 10 has a strength of the filament 13 of 200 kg / in order to obtain a lightweight and sufficient strength.
It should be at least mm ² .

In order to make the belt layer effectively function, the number E of filaments 13 per 5 cm width of the reinforcing ply is 100 to 240 filaments / 5 cm.
^{3. The} filament density (S × E) obtained by multiplying the cross-sectional area S (unit: mm ² ) of the filament 13 by the number E of implantation is 4.
It is set to 78 or higher. The filament density is 4.
When it is less than 78, steering stability and abrasion resistance are deteriorated such as insufficient tread rigidity. Therefore, in order to improve the performance, the filament density is 7.0 or more, more preferably 7.3 or more.

Further, in the reinforcing plies 7A and 7B, it is preferable that the distance a between the adjacent reinforcing cords 10 is 0.75 to 0.95 times the filament diameter D, and when the distance a is smaller than 0.75D. Since the rubber gauge between the cords is insufficient, the cord looseness is likely to be caused by the shearing force acting between the cords. On the other hand, when the distance a is larger than 0.95D, the filament density is reduced, and as a result, the tread rigidity becomes insufficient and the steering stability and wear resistance are deteriorated.

The reinforcing cord 10 can also be used as a breaker cord of a breaker layer in a tire having a bias structure. In such a case, the reinforcing cords are arranged at an angle of 30 to 40 degrees with respect to the tire equator.

(Specific Example) A radial tire having a tire size of 185 / 65R14 having the structure shown in FIG. 1 was prototyped based on the specifications shown in Table 1, and the weight, wear resistance, steering stability and noise performance of each test tire were tested. Was compared with the conventional tire 1 and the conventional tire 2.

The steering stability is a 5-point method based on the driver's sensory evaluation of the steering stability when the tire is mounted on a passenger car (1600 cc, FF vehicle) under the conditions of standard rim and standard internal pressure, and the test course is run. Scored in. 3 is the average, and the larger the value, the better.

The noise performance was measured by a coasting test specified in JASOC606. The passenger car was used to coast along a straight test course at an engine off state and a passing speed of 55 km / h to a side of the running center. The passing noise was measured by a stationary microphone placed at a height of 1.2 m from the road surface at a distance of 0.5 m, and the maximum level at that time was shown in dB (A).

[0031]

[Table 1]

[0032]

Since the present invention is constructed as described above, it is possible to reduce the thickness of the cord while ensuring the required bending rigidity and compression rigidity, and especially when used as a belt cord, wear resistance and steering The weight of the tire can be reduced while maintaining stability and noise.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a tire showing an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a part of the reinforcing ply.

FIG. 3 is a plan view showing the reinforcing cord.

FIG. 4 is a plan view showing another example of the reinforcing cord.

FIG. 5 is a plan view of a cord for explaining a conventional technique.

[Explanation of symbols]

 2 tread part 3 sidewall part 4 bead part 5 bead core 6 carcass 7 reinforcing layer 7A, 7B reinforcing ply 10 reinforcing cord 13 filament

Claims (6)

[Claims] 1. A filament made of 2 to 6 steels,
Without twisting, the filaments are arranged side by side in the same plane and aligned in parallel, and adjacent filaments are intermittently bonded, and the diameter of each filament is 0.15 to 0.3 mm.
Reinforcement cord for tires in the range of. 2. A carcass folded back from the tread portion to the sidewall portion around the bead core of the bead portion, and a reinforcing cord disposed radially outside the carcass and inside the tread portion and embedded in a topping rubber. The reinforcing cord is provided with at least one reinforcing ply, and the reinforcing cord has 2 to 6 steel filaments arranged side by side in the same plane without twisting and aligned in parallel with each other. A pneumatic tire having a band shape in which filaments are intermittently adhered, and the diameter of each filament is in the range of 0.15 to 0.3 mm and the thickness of the reinforcing ply is 1 mm or less. 3. The pneumatic tire according to claim ² , wherein the filament has a strength of 200 kg / mm ² or more. 4. The pneumatic tire according to claim 2, wherein the reinforcing ply has a number E of filaments per 100 cm of a width of the reinforcing ply of 100 to 240 filaments / 5 cm. 5. The reinforcing cord has a distance d between adjacent filaments of 0.2 to 0.3 of a diameter D of the filament.
In addition, the reinforcing ply has a distance a between adjacent reinforcing cords of 0.75 of the filament diameter D.
The pneumatic tire according to claim 2, wherein the pneumatic tire is 0.95 times. 6. The reinforcing ply has a filament density (S × E) obtained by multiplying the cross-sectional area S (unit: mm ² ) of the filament by the number E of driving the cords, to be 4.78 or more. The pneumatic tire according to claim 4.