JPH1143877A - Rubber material-reinforcing steel cord and pneumatic radial tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel cord generating slight lowering of cord strength by fretting wear and to provide a pneumatic radial tire having excellent durability hardly generating separation accident or cut through accident. SOLUTION: This rubber material-reinforcing steel cord 1 is obtained by using a wrapping wire 3 comprising by twisting more than two steel filaments in the steel cord 1 in which the wrapping wire 3 is spirally wound around a steel cord main body 2 comprising by twisting plural steel filaments.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel cord for reinforcing rubber articles such as rubber hoses, conveyor belts, pneumatic tires, and more particularly to a plurality of steel cords.
A radial carcass and / or belt is formed from a steel cord for reinforcing a rubber article in which a wrapping wire is spirally wound around a steel cord body formed by twisting filaments and a rubber-coated layer of the steel cord. Pneumatic radial tires.

[0002]

2. Description of the Related Art Conventionally, in a steel cord used as a reinforcing material for rubber articles such as rubber hoses, conveyor belts, pneumatic tires, etc., around a cord body formed by twisting a plurality of steel filaments. It is known that a wrapping filament is spirally wound to strongly restrain a steel filament constituting a cord. In other words, the wrapping filament prevents the filaments that make up the cord from falling apart when cutting the steel cord,
When a steel cord is embedded in rubber to form a sheet, it plays a role in preventing or suppressing the sheet end from warping or deforming into a curl shape.

[0003]

As described above, the wrapping filament plays a very important role in the stage of producing the steel cord itself and the stage of producing the composite of the cord and rubber. After steel cord is incorporated as a reinforcing material for rubber articles such as hoses, conveyor belts and pneumatic tires, the friction and contact pressure between the steel filament located on the outermost layer of the steel cord body and the wrapping filament The secondary bending caused by fretting has the disadvantage that the cord strength is reduced due to fretting wear and the cord generates heat.

An object of the present invention is to solve the above-mentioned disadvantages of the prior art, to provide a steel cord in which the strength of the cord is hardly reduced due to fretting wear, and to prevent separation failure and cut-through failure. And a highly durable pneumatic radial tire.

[0005]

In order to achieve the above object, a steel cord according to the present invention has a wrapping wire spirally wound around a steel cord body formed by twisting a plurality of steel filaments. A steel cord for reinforcing rubber articles, wherein the wrapping wire is formed by twisting two or more steel filaments.

In order to achieve the above object, in the steel cord according to the present invention, the angle formed between the steel filament of the wrapping wire and the steel filament located on the outermost layer of the steel cord body is different from each other. When measured at a contact point, the angle is preferably 40 degrees or less.

In order to achieve the above object, in the steel cord according to the present invention, the wrapping wire preferably has an elongation at break of 3.5% or more.

In order to achieve the above object, in a steel cord according to the present invention, the wrapping wire is 1 ×.
It is preferable that the structure is 2.

In order to achieve the above object, in the steel cord according to the present invention, the wrapping wire is 1 ×
It is preferable that the structure is 3.

In order to achieve the above object, in the steel cord according to the present invention, it is preferable that the twisting direction of the outermost sheath of the steel cord body and the twisting direction of the wrapping wire are different from each other.

In order to achieve the above object, a pneumatic tire according to the present invention comprises a bead core provided on left and right bead portions, and a bead core extending from a crown portion to both bead portions via both side portions. A pneumatic tire having a radial carcass wound around and moored to a bead portion, and a belt disposed radially outside the crown portion of the radial carcass, wherein the radial carcass and / or the belt are A layer in which a steel cord in which a wrapping wire in which two or more steel filaments are twisted is spirally wound around a steel cord body in which a plurality of steel filaments are twisted. It is a pneumatic radial tire characterized by being formed with.
To achieve the above object, the steel cord forming the radial carcass and / or the belt of the pneumatic tire according to the present invention is located on the outermost layer of the steel filament of the wrapping wire and the steel cord body. Angle with the steel filament
When measured at a point where they come into contact with each other, the wrapping wire has an elongation at break of not more than 40 degrees, which is 3.5 degrees.
% Or more, the wrapping wire has a structure of 1 × 2 or 1 × 3, and the twist direction of the outermost sheath of the steel cord body and the twist direction of the wrapping wire are different from each other. Is preferred.

The steel cord according to the present invention is configured as described above, and in particular, twists two or more steel filaments around a steel cord body formed by twisting a plurality of steel filaments. The wrapping wire is spirally wound, so that the tension in the axial direction of the cord can be controlled to be lower than the conventional method of wrapping a single steel filament. , And an increase in the code strong utilization rate is achieved.

As described above, the steel cord according to the present invention is characterized in that the angle formed between the steel filament of the wrapping wire and the steel filament of the outermost layer of the steel cord body is measured at a point where they contact each other. Is preferably 40 degrees or less. This is because when the angle between the two filaments is 40 degrees or less, the contact between the two becomes close to the line contact and the contact pressure becomes extremely small.
Fretting and heat generation due to friction are reduced, and separation failure due to deterioration of adhesive strength is suppressed.
This is because the occurrence of secondary bending is less likely to cause breakage of the cord due to an external cut input or the like.

As described above, the steel cord according to the present invention has an elongation at break of the wrapping wire of 3.5%.
It is preferable that it is above. This is to suppress cutting of the wrapping wire in the process of manufacturing a steel cord, to increase cord productivity and reduce the cost of the cord.

As described above, in the steel cord according to the present invention, it is preferable that the wrapping wire has a 1 × 2 or 1 × 3 structure in order to increase the production efficiency of the cord.

In the steel cord according to the present invention, as described above, the twist direction of the outermost sheath of the steel cord body and the twist direction of the wrapping wire are preferably different from each other. This is done by reversing the twisting direction of both, improving the properties of the steel cord body, preventing the filaments constituting the cord from falling apart when cutting the steel cord, -This is for preventing or suppressing the sheet end from warping or deforming into a curl when the cord is embedded in rubber to form a sheet.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The steel cords of Examples 1 to 4 according to the present invention, the steel cords of Conventional Examples 1 to 3, and a belt formed of a rubber-coated layer of these steel cords will be described below. The pneumatic radial tire for a construction vehicle provided will be described. Tire size is
Both are 40.00R57.

FIG. 1 is a sectional view of a steel cord according to the first embodiment. The steel cord 1 of the first embodiment is 7 × (3+
9 + 15) × 0.24 + 1 × 2 × 0.19, as shown, three steel filaments are twisted in the Z direction at a pitch of 6.5 mm, and nine steels are wound around a core.・ 12.5mm filament
Twisted in the Z direction at a pitch of
15 steel filaments around 19mm
7 strands twisted in the Z direction at a pitch of 7 mm to form a second sheath are twisted in the S direction at a pitch of 60 mm to form a steel cord body 2.
A wrapping wire 3 in which two steel filaments are twisted in the Z direction at a pitch of 1.3 mm around the cord body 2 is spirally wound in the Z direction at a pitch of 20 mm. The diameter of the filament forming the steel cord body 2 is 0.2
4 mm, and the diameter of both filaments forming the wrapping wire 3 is 0.19 mm. When the angle between the steel filament of the wrapping wire 3 and the steel filament located on the outermost layer of the steel cord body 2 is measured at a point where they contact each other, the wrapping wire 3 As described above, it has a 1 × 2 structure. The twisting direction of the outermost sheath of the steel cord body 2, that is, the seven strands is the S direction as described above, and the twisting direction (spiral direction) of the wrapping wire 3 is different from the Z direction. The cord strength of the steel cord 1 of the first embodiment is 2320 kgf.

FIG. 2 is a sectional view of a steel cord according to the second embodiment. The steel cord 1 of the second embodiment is 7 × (3+
9) A structure of × 0.36 + 1 × 2 × 0.19, as shown, three steel filaments of 10 mm
Around the core twisted in the S direction at a pitch of 9
7 steel strands were twisted in the S direction at a pitch of 18 mm to form 7
A wrapping wire formed by twisting in the S direction at a pitch of 5 mm to form a steel cord body 2 and twisting two steel filaments around the steel cord body 2 at a pitch of 1 mm in the Z direction. 3 is 2
It is wound spirally in the Z direction at a pitch of 0 mm. The diameter of the filament forming the steel cord body 2 is 0.36 mm, and the diameter of the filament forming the wrapping wire 3 is 2 mm.
Both books are 0.19 mm. When the angle between the steel filament of the wrapping wire 3 and the steel filament located on the outermost layer of the steel cord body 2 is measured at a point where they contact each other, the angle is 30 degrees.
The wrapping wire 3 has a 1 × 2 structure as described above. As described above, the twisting direction of the outermost sheath of the steel cord body 2, that is, the seven strands is the S direction, and the twisting direction (spiral direction) of the wrapping wire 3 is different from the Z direction.
The cord strength of the steel cord 1 of Example 2 is 2320
kgf.

FIG. 3 is a sectional view of a steel cord according to the third embodiment. Steel cord 1 of Example 3 is 7 × 7 ×
It has a structure of 0.40 + 1 × 2 × 0.19. As shown, seven strands of seven steel filaments twisted in the S direction at a pitch of 12.7 mm are 50 m long.
The steel cord body 2 is formed by twisting in the Z direction at a pitch of m, and around the steel cord body 2,
Wrapping wire 3 made by twisting two steel filaments at a pitch of 1 mm in the S direction is 20 m
It is spirally wound in the S direction at a pitch of m. The diameter of each filament forming the steel cord body 2 is 0.40 mm,
The diameter of both filaments forming the wire 3 is 0.19 mm. When the angle between the steel filament of the wrapping wire 3 and the steel filament located on the outermost layer of the steel cord body 2 is measured at a point where they contact each other, the wrapping wire 3 As described above, it has a 1 × 2 structure.
The outermost sheath of the steel cord body 2, that is, the twist direction of the seven strands is the Z direction as described above,
Twist direction of the wrapping wire 3 (spiral direction)
Are twist directions different from each other. The cord strength of the steel cord 1 of the third embodiment is 1270 kgf.

FIG. 4 is a sectional view of a steel cord according to the fourth embodiment. The steel cord 1 of the fourth embodiment is 7 × (3+
9 + 15) × 0.24 + 2 × 2 × 0.15, as shown, three steel filaments are twisted in the Z direction at a pitch of 6.5 mm, and nine steels are wound around a core.・ 12.5mm filament
Twisted in the Z direction at a pitch of
15 steel filaments around 19mm
7 strands twisted in the Z direction at a pitch of 7 mm to form a second sheath are twisted in the S direction at a pitch of 60 mm to form a steel cord body 2.
A wrapping wire 3 formed by twisting two steel filaments in the Z direction at a pitch of 2 mm around the cord body 2 at a pitch of 2.3 mm and wrapping wires 3 at a pitch of 20 mm It is wound spirally in the Z direction. Steel cord body 2
The diameter of the filament forming
mm, and the diameter of the filaments forming the wrapping wire 3 is 0.15 mm for all four filaments. When the angle formed between the steel filament of the wrapping wire 3 and the steel filament located on the outermost layer of the steel cord body 2 is 0 degree when measured at a point where they contact each other, the wrapping wire 3 As described above, it has a 1 × 2 structure. The twisting direction of the outermost sheath of the steel cord body 2, that is, the seven strands is the S direction as described above, and the twisting direction (spiral direction) of the wrapping wire 3 is different from the Z direction. The cord strength of the steel cord 1 of the fourth embodiment is 2320 kgf.

FIG. 5 is a sectional view of a steel cord according to the first conventional example. The steel cord 1 of the conventional example 1 is 7 × (3+
9 + 15) × 0.24 + 1 × 2 × 0.19, as shown, three steel filaments are twisted in the Z direction at a pitch of 6.5 mm, and nine steels are wound around a core.・ 12.5mm filament
Twisted in the Z direction at a pitch of
15 steel filaments around 19mm
The steel cord main body 2 is formed by twisting seven strands in the Z direction at a pitch of 60 mm and twisting in the S direction at a pitch of 60 mm to form a second sheath. One strand is formed around the steel cord main body 2. A steel filament 3 is spirally wound in the Z direction at a pitch of 5 mm. In other words, the steel cord of the first conventional example has the same structure as the steel cord of the first embodiment except that the wrapping wire 3 is formed of one steel filament. The diameter of the filaments forming the steel cord body 2 is 0.24.
mm, and the diameter of the wrapping filament 3 is 0.3 mm.
25 mm. The angle formed between the wrapping filament 3 and the steel filament located on the outermost layer of the steel cord body 2 is 68 degrees when measured at the place where they contact each other. The twisting direction of the outermost sheath of the steel cord body 2, that is, the seven strands is the S direction as described above, and the twisting direction (spiral direction) of the wrapping filament 3 is different from the Z direction. The cord strength of steel cord 1 of Conventional Example 1 is 2290 kgf.

FIG. 6 is a sectional view of a steel cord according to the second conventional example. The steel cord 1 of the conventional example 2 is 7 × (3+
9) A structure of × 0.36 + 1, as shown in FIG.
Nine steel filaments are wound around a core made by twisting steel filaments in the S direction at a pitch of 10 mm.
Seven strands each having a sheath formed by twisting filaments in the S direction at a pitch of 18 mm are twisted in the S direction at a pitch of 45 mm to form a steel cord body 2. A steel filament 3 is wound spirally in the Z direction at a pitch of 10 mm. In other words, Conventional Example 2
Has the same structure as the steel cord of Example 2 except that the wrapping wire 3 is formed of one steel filament. The diameter of each filament forming the steel cord body 2 is 0.36 mm, and the diameter of the wrapping filament 3 is 0.25 mm. The angle formed between the wrapping filament 3 and the steel filament located on the outermost layer of the steel cord body 2 is 79 degrees when measured at points where they contact each other. The twist direction of the outermost sheath of the steel cord body 2, that is, the seven strands is the S direction as described above, and the twist direction (spiral direction) of the wrapping filament 3 is Z.
The direction is a twist direction different from each other. The cord strength of the steel cord 1 of the second embodiment is 2290 kgf.

FIG. 7 is a sectional view of a steel cord according to the third conventional example. Conventional example 3 steel cord 1 is 7 × 7 ×
The steel cord body 2 has a structure of 0.40 + 1, and seven strands of seven steel filaments twisted in the S direction at a pitch of 12.7 mm as shown in the drawing are twisted in the Z direction at a pitch of 50 mm. And around the steel cord body 2, one steel cord is formed.
The filament 3 is spirally wound in the S direction at a pitch of 5 mm. In other words, the steel cord of the conventional example 3 has the same structure as the steel cord of the example 3 except that the wrapping wire 3 is formed of one steel filament. steel·
The diameter of each filament forming the cord body 2 is 0.40 mm, and the wrapping filament 3
Has a diameter of 0.25 mm. The angle formed between the wrapping filament 3 and the steel filament located on the outermost layer of the steel cord body 2 is 65 degrees when measured at the place where they contact each other. The twisting direction of the outermost sheath of the steel cord body 2, that is, the seven strands is the Z direction as described above, and the twisting direction (spiral direction) of the wrapping filament 3 is different from the S direction. The cord strength of the steel cord 1 of the third embodiment is 1270 kgf.

Using the seven types of steel cords according to the first to fourth embodiments and the first to third prior arts according to the present invention, a cord rubber layer is formed by a rubber-coated layer of each steel cord; Twenty pneumatic radial tires for construction vehicles each using the cord / rubber layer for the third and fourth belt layers of the six belt layers were prototyped, and the tires were allowed to run on the ground, and then subjected to separation resistance and resistance to separation. A comparative test of cut penetration performance was performed. The tire size is 40.00R57. Run the test tire on the road, remove the tire from the vehicle in a state where the tread rubber is completely worn, calculate the separation occurrence rate from the number of tires where separation has occurred for each of 20 tires, and The cut penetration occurrence rate was calculated from the number of tires where cut penetration occurred. That is, if the separation occurs in one of the 20 tires, the separation occurrence rate is 5%. Similarly, the cut-through occurs in the four tires out of the 20 tires. In this case, the cut penetration rate is 20%.

According to the results of the comparison test of the separation resistance, the tires using the steel cords of Examples 1 to 4 according to the present invention have separation rates of 5%, 5%, 10% and 5%, respectively. However, the tires using the steel cords of Conventional Examples 1 to 3 had separation rates of 20%, 20% and 40%, respectively. According to the comparative test results of the cut penetration resistance, the tires using the steel cords of Examples 1 to 4 according to the present invention all have a cut penetration rate of 5%.
%, The tires using the steel cords of Conventional Examples 1 to 3 all have a cut penetration occurrence rate of 20%.
Met.

Tables 1 and 2 show the comparison test results of the separation resistance and the cut penetration resistance, together with the outline of the steel cord used for the radial carcass of the test tire.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

As can be seen from the results shown in Table 1,
It can be seen that the tire using the steel cord of the example according to the present invention has better separation resistance and cut penetration resistance than the tire using the conventional steel cord.

[Brief description of the drawings]

FIG. 1 is a sectional view of a steel cord according to an embodiment.

FIG. 2 is a sectional view of a steel cord according to the embodiment.

FIG. 3 is a sectional view of a steel cord according to the embodiment.

FIG. 4 is a sectional view of a steel cord according to the embodiment.

FIG. 5 is a sectional view of a conventional steel cord.

FIG. 6 is a sectional view of a conventional steel cord.

FIG. 7 is a sectional view of a conventional steel cord.

[Explanation of symbols]

 1 Steel cord 2 Steel cord body 3 Spiral wire (filament)

Claims (6)

[Claims] 1. A steel cord for reinforcing a rubber article in which a wrapping wire is spirally wound around a steel cord body formed by twisting a plurality of steel filaments, wherein the wrapping wire is two or more. A steel cord for reinforcing rubber articles, comprising twisting steel filaments. 2. The angle between the steel filament of the wrapping wire and the steel filament located on the outermost layer of the steel cord body is less than 40 degrees when measured at the point where they contact each other. The steel cord for reinforcing a rubber article according to claim 1, wherein: 3. The steel cord for reinforcing rubber articles according to claim 1, wherein the wrapping wire has a 1 × 2 structure. 4. The steel cord for reinforcing rubber articles according to claim 1, wherein said wrapping wire has a 1 × 3 structure. 5. The steel cord for reinforcing rubber articles according to claim 1, wherein the twisting direction of the outermost sheath of the steel cord body and the twisting direction of the wrapping wire are different from each other. 6. A radial carcass which extends from a crown portion to both bead portions via both side portions, and is wound around the bead core and moored to the bead portions. 6. A pneumatic tire comprising: a belt disposed radially outward of a crown portion of the radial carcass, wherein the radial carcass and / or the belt are formed of a steel for reinforcing rubber articles according to any one of claims 1 to 5. A pneumatic radial tire, wherein the cord is formed of a rubber-coated layer.