CN111535062A - Steel wire cord for 1+ 7-ply radial tire - Google Patents

Abstract

The invention discloses a steel cord for a 1+7-strand radial tire, comprising a core-strand steel wire and an outer-layer-strand-strand steel wire, wherein the outer-layer-strand-strand steel wire is arranged on the core-strand-strand wire along the circumferential direction The outside of the steel wire, the core strand steel wire includes at least three core strands of the first layer of steel wire and at least nine core strands of the second layer of steel wire braided and twisted, and the outer layer strand wire steel wire includes at least one outer layer strand The first layer of steel wires and at least six outer-layer strands of second-layer steel wires are braided and twisted; the gap between the seven outer-layer strands of steel wires in the present invention is relatively large, which is beneficial for the rubber to fully penetrate into the core-strand steel wires, avoiding the Sufficient rubber penetration results in point-contact friction between the layers of steel wire, thereby avoiding the problem of failure of the load-carrying capacity of the steel cord due to wear.

Description

A kind of steel cord for 1+7 strands radial tire

technical field

The invention relates to a steel cord for 1+7 radial tires, belonging to the technical field of steel cords.

Background technique

Steel cord is an important part of radial engineering tire skeleton material. The steel cord with 7×7×d+0.15HT structure commonly used in radial engineering tires consists of one 7×d core strand and six 7×d strands. The outer strands are braided and twisted with a 0.15mm outer wrapping wire. The core strands and the outer strands are of the same structure, the diameter of the steel wire is the same, the twist direction of the 7×d structure is S, and the twist pitch is 12.5 mm, the twist direction of the six outer layers is Z, the twist distance is 20.0mm, the outer winding twist direction is S, and the twist distance is 5.0mm. Smaller, the rubber cannot effectively penetrate into the core strand steel wire resulting in a high air content inside the cord. The structure of steel cord, its strength, flexural rigidity, and adhesion to rubber have a direct impact on the tire, and the control of the steel cord production process alone cannot completely compensate for the defects existing due to unreasonable structural design. During the use of radial tires, it is easy to cause the failure of the bearing capacity of the cord due to insufficient strength of the steel cord or corrosion and wear of the steel wire.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a kind of steel cord for 1+7 strands radial tire, in order to solve the problem of insufficient strength of the prior art steel cord, small gap between outer strands, rubber can not effectively penetrate into the core strand steel wire and cause the inside of the cord Defects with higher air content.

A steel cord for a 1+7-strand radial tire, comprising a core-strand steel wire and an outer-layer-strand-strand steel wire, wherein the outer-layer-strand-strand steel wire is arranged on the outside of the core-strand-strand steel wire along a circumferential direction, The core strand steel wire comprises at least three core strands of the first layer of steel wire and at least nine core strands of the second layer of steel wire braided and twisted, and the outer layer strand wire steel wire includes at least one outer layer strand of the first layer of steel wire It is twisted with at least six outer strands of second-layer steel wire.

Preferably, there are at least seven groups of the outer-layer stranded steel wires, and the outer-layer stranded steel wires are braided along the core-stranded wire to form at least seven outer-layer stranded steel wires that are uniformly twisted and distributed in one Strand core strand strand wire.

Preferably, the diameters of the first layer of steel wires of the core strand and the first layer of steel wires of the outer layer strands are the same.

Preferably, the diameters of the first-layer steel wires of the core strand and the first-layer steel wires of the outer-layer strands range from 0.165 to 0.38 mm.

Preferably, the twist directions of the core strands and the outer strands are opposite.

Preferably, the lay length of the second layer of steel wires of the core strands is the same as that of the second layer of steel wires of the outer layer strands.

Preferably, the lay length of the wires in the first layer of the core strand is 0.5 times the lay length of the wires in the first layer of the outer layer.

Preferably, the first layer of steel wire of the outer layer strands is not twisted.

Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) the gap between the seven outer layer strand wires of the present invention is larger, which is conducive to the rubber fully infiltrating into the core strand wires, and avoids the lack of penetration due to lack of penetration. Sufficient rubber leads to point contact friction between the layers of steel wires, thereby avoiding the problem of failure of the bearing capacity of steel cords due to wear;

(2) The present invention improves the corrosion resistance, fatigue resistance, impact resistance and adhesion retention of the tire, and increases the service life of the tire.

Description of drawings

1 is a schematic cross-sectional view of a steel cord for a multi-strand radial tire of the present invention;

FIG. 2 is a schematic cross-sectional view of a steel cord commonly used in the prior art.

In the picture: 1. The first layer of core strands; 2. The second layer of core strands; 3. The core strands; 5. The outer strands; 7. The first layer of outer strands; 8. Outer strands second layer of steel wire.

Detailed ways

In order to make the technical means, creative features, achievement goals and effects realized by the present invention easy to understand, the present invention will be further described below with reference to the specific embodiments.

As shown in Figure 1, a 1+7-strand steel cord for radial tires is composed of a core strand steel wire 3 and seven outer strand strand steel wires 5. The cross-section of the steel cord is Round, seven outer strands of wire 5 are twisted around the core strand 3 to form a structure in which seven outer strands 5 are evenly twisted around one core strand 3 . The core-strand wire 3 is made of three core-strand first-layer steel wires 1 and nine core-strand second-layer steel wires 2, and the nine core-strand second-layer steel wires 2 surround the three core-strand first-layer steel wires 1 Twisting; the outer strand wire 5 is braided and twisted by one outer strand first-layer steel wire 7 and six outer-layer second-layer steel wires 8; the core-strand first-layer steel wire 1 and the outer-layer strands The diameter of one layer of steel wires 7 is the same, and the diameter ranges from 0.165 to 0.38 mm. The twist direction of the core strand wire 3 is opposite to that of the outer layer strand wire 5; The pitch is 0.5 times the twist pitch of the first-layer steel wire 7 of the outer-layer strand, and the first-layer steel wire a1 of the outer-layer strand-strand wire 5 has no twist.

By changing the structure of the steel cord, the invention makes up for the defects caused by the unreasonable structural design of the steel cord, improves the strength, rubber penetration performance, impact resistance and fatigue resistance of the steel cord, and reduces the number of tire steel cord strands and tire cords. The air content between strands increases tire cord strength rating and tire life.

In this embodiment, the strength grades of the steel wires in the core strand wire 3 and the outer layer strand wire 5 are normal strength NT, high strength HT, super high strength ST, extra high strength UT or very high strength MT; The invention is suitable for braiding and twisting steel wires of different strength grades of ordinary strength NT, high strength HT, ultra-high strength ST, ultra-high strength UT or extremely high strength MT, and can improve the strength requirements of the braided steel cords, and the glue penetration. performance and impact and fatigue resistance.

Example 1:

In this embodiment, the diameter d1 of the steel wire 3 of the core strand is the same as the diameter d2 of the steel wire 5 of the outer layer. The diameter of each layer of steel wire in the outer layer strand wire 5 is 0.22 mm. The lay length of the first layer of steel wire 1 of the core strand is 6.3mm, the lay length of the second layer of steel wire 2 of the core strand is 12.5mm, and the lay length of the second layer of steel wire 8 of the outer layer is 12.5mm. The core strand wire 3 and the outer layer strand wire 5 adopt different twist directions. The core strand wire 3 has a Z twist, the outer layer strand 5 has an S twist, and the cord twist is Z. Twist, in this embodiment, the 3+9×0.22+7×7×0.22 steel cord structure is used for steel cords for engineering vehicle radial tire reinforcement.

Table 1 is the performance index comparison table of the 7×7×0.25+0.15HT structure steel cord commonly used in radial tires in the prior art and the first embodiment of the present invention:

Table 1

Fig. 2 is a schematic cross-sectional view of a 7×7×d+0.15 structural steel cord commonly used in the prior art. It can be seen from Fig. 1, Fig. 2 and Table 1 that the 7×7×0.25+0.15HT structural steel cord has a The diameter is 2.52mm, the second layer of steel wire in the core strand wire D1 and the second layer of steel wire in the outer layer strand wire D2 are S-twisted, the six outer layer strands are Z-twisted, and the outer-layer strand wire is D3. The twist direction is S twist, the twist distance of the second layer of the core strand wire D1 and the outer layer strand wire D2 is 12.5mm, the twist distance of the six outer layer strands is 20.0mm, and the outer layer strand wire is 20.0mm. The twist length of the steel wire D3 is 5.0mm, the breaking force is ≥6350N, the diameter of the cord is 2.52mm, the breaking force/linear density is 320.7N/(/g/m), and the adhesive force is ≥1650N/25mm; the embodiment of the present invention The diameter of the first steel cord is 2.20mm, the twist direction of the core strand steel wire D1 is Z twist, the twist distance is 6.3/12.5mm, and the outer layer strand steel wire D2 steel wire is S twist, and the twist distance is 12.5mm , the twist length of the seven-strand outer strand wire steel wire is 22.0mm, the breaking force is ≥6550N, the breaking force/linear density is 351.2N/(mm), and the adhesive force is ≥1700N/25mm; Example 1 Using steel strands with ultra-high strength grades, the strength, glue penetration rate and fatigue resistance of steel cords are improved by increasing the number of strands.

Embodiment 2:

In this embodiment, the diameter d1 of the steel wire 3 of the core strand is the same as the diameter d2 of the steel wire 5 of the outer layer. The diameter of each layer of steel wire 5 and the outer layer strand wire is 0.22mm; the twist length of the first layer of the core wire 1 is 6.3mm, and the twist length of the second layer of the core wire 2 is 12.5mm. , and the twist pitch of the second layer of steel wire braiding of the outer strand is 12.5mm. The core strand wire 3 and the outer layer strand wire 5 adopt different twist directions. The core strand wire 3 has a Z twist, the outer layer strand 5 has an S twist, and the cord twist is Z. Twist, the 3+9×0.22+7×7×0.22 steel cord structure of this embodiment is used for steel cords for engineering vehicle radial tire reinforcement.

Table 2 is the performance index comparison table of the 7×7×0.22+0.15HT structural steel cord commonly used in radial tires in the prior art and the second embodiment of the present invention:

Table 2

Fig. 2 is a schematic cross-sectional view of a 7×7×d+0.15 structural steel cord commonly used in the prior art. It can be seen from Fig. 1, Fig. 2 and Table 1 that the 7×7×0.22+0.15HT structural steel cord has a The diameter is 2.24mm, the second-layer steel wire in the core strand wire D1 and the second-layer steel wire in the outer-layer strand wire D2 are S-twisted, the six outer-layer strand-strand steel wires are Z-twist, and the outer-layer strand steel wire is D3. The twist direction is S twist, the twist distance of the second layer of the core strand wire D1 and the outer layer strand wire D2 is 12.5mm, the twist distance of the six outer layer strands is 20.0mm, and the outer layer strand wire is 20.0mm. The twist length of the steel wire D3 is 5.0mm, the breaking force is ≥5120N, the diameter of the cord is 2.24mm, the breaking force/linear density is 336.8N/(/g/m), and the adhesive force is ≥1550N/25mm; the embodiment of the present invention The diameter of the first steel cord is 2.20mm, the twist direction of the core strand steel wire D1 is Z twist, the twist distance is 6.3/12.5mm, and the outer layer strand steel wire D2 steel wire is S twist, and the twist distance is 12.5mm , the twist length of the seven-strand outer strand wire steel wire is 22.0mm, the breaking force is ≥6550N, the breaking force/linear density is 351.2N/(mm), and the adhesive force is ≥1700N/25mm; Example 1 Using steel strands with ultra-high strength grades, the strength, glue penetration rate and fatigue resistance of steel cords are improved by increasing the number of strands.

From the above comparison, it can be seen that when radial tires of the same density are produced, the strength of the radial tire produced by the present invention is increased by 4-9.5% compared with the radial tire produced by the prior art, and the performance of the cord leakage and fatigue resistance is greatly improved. improve. The invention can effectively reduce the production cost of the engineering vehicle radial tire and prolong the service life of the engineering vehicle radial tire.

The embodiments of the present invention are only examples. According to different applications, in the 3+9×d1+7×7×d2 structure of the present invention, the steel wire in the core strand wire D1 and the steel wire in the outer layer strand wire D2 can use different wire diameters and strengths Proportion, twist direction is divided into ZZ/S/Z or SS/Z/S.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the technical principle of the present invention, several improvements and modifications can also be made. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (8)

1. A steel cord for a 1+7-strand radial tire, characterized in that it comprises a core-strand strand wire (3) and an outer-layer strand-strand steel wire (5), the outer-layer strand-strand steel wire (5) It is arranged on the outside of the core-strand wire (3) in the circumferential direction, and the core-strand wire (3) includes at least three core-strand first-layer steel wires (1) and at least nine core-strand second-layer steel wires (2) Braided and twisted, the outer layer strand wire (5) comprises at least one outer layer first layer steel wire (7) and at least six outer layer second layer steel wires (8) braided and twisted . 2 . The steel cord for a multi-strand radial tire according to claim 1 , wherein at least seven groups of the outer-layer strand steel wires (5) are provided, and the outer-layer strand-strand steel wires (5) Twisting along the core strand wire (3) to form at least seven outer layer strand wires (5) uniformly twisted on one core strand wire (3). 3. A 1+7-strand radial tire steel cord according to claim 1, characterized in that the diameters of the first-layer steel wires (1) of the core strands and the first-layer steel wires (7) of the outer-layer strands same. 4. A 1+7-strand steel cord for radial tires according to claim 3, characterized in that the diameters of the first-layer steel wires (1) of the core strands and the first-layer steel wires (7) of the outer-layer strands The range is 0.165 to 0.38mm. 5. A kind of 1+7-strand steel cord for radial tire according to claim 1, characterized in that, the twist of the steel wire in the core strand wire (3) and the outer layer strand wire (5) to the opposite. 6. A 1+7-strand steel cord for radial tires according to claim 1, characterized in that the lay length of the second-layer steel wire (2) of the core strand and the second-layer steel wire (8) of the outer layer strand same. 7. A 1+7-strand steel cord for radial tires according to claim 1, wherein the lay length of the first layer of steel wires (1) of the core strands is the first layer of steel wires (7) of the outer layers. ) 0.5 times the twist pitch. 8 . The 1+7-strand steel cord for radial tires according to claim 1 , wherein the outer strands of the first-layer steel wires ( 7 ) are not twisted. 9 .

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