A steel cord and radial tire

Abstract

This invention discloses a steel cord and radial tire in the field of steel cord technology, aiming to optimize the structure and achieve good geometric characteristics in the contact between steel wires. It includes an inner layer and an outer layer; the inner layer consists of four steel wires twisted together with a diameter of d1; the outer layer consists of ten steel wires twisted together with a diameter of d2; the ratio of the inner layer steel wire diameter d1 to the outer layer steel wire diameter d2 is d1 = d2 + 0.01 mm; the inner and outer layers have the same twist direction. This invention can be used for belt layers and tire carcass reinforcement, and can reduce the thickness of the cord and the amount of cord used while maintaining the same density and strength, thus providing a high-performance and lightweight radial tire.

Description

Technical Field

[0001] This application relates to the field of steel cord technology, and particularly to a steel cord and radial tire. Background Technology

[0002] Steel cord is an important component of tire skeleton materials. In existing technologies, one type of structure includes: an inner layer composed of three steel wires and an outer layer composed of nine steel wires twisted together, with the inner three wires and outer nine wires having the same twist direction and pitch. The inner wire diameter is d1, and the outer wire diameter is d2. This structure is formed in a single twisting process. Another type of structure includes: an inner layer composed of one core steel wire and six steel wires twisted together, and an outer layer composed of twelve steel wires twisted together. The inner core steel wire is untwisted, and the inner six wires and outer twelve wires have the same twist direction. The pitch of the inner six wires is 0.468 to 0.5 times that of the outer twelve wires. The inner core wire diameter is d1, and the inner and outer wire diameters are both d2. This structure requires secondary twisting processing.

[0003] To optimize the structure, it is necessary to design the wire diameter so that the contact between the wires has good geometric characteristics. This contact load depends on the load that each wire can withstand, that is, the load on the cord divided by the number of wires. This invention proposes a steel cord and radial tire, which reduces the complexity of the manufacturing process and can be used for belt layer and carcass reinforcement. With the same density and strength, the cord thickness and cord usage can be reduced, which can provide a high-performance and lightweight radial tire. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a steel cord and radial tire, which aims to reduce the complexity of the manufacturing process, reduce the thickness of the cord and the amount of cord used while maintaining the same density and strength, and provide a high-performance and lightweight radial tire.

[0005] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution:

[0006] On one hand, the present invention provides a steel cord, comprising:

[0007] The inner layer comprises four steel wires twisted together with a diameter of d1; the outer layer comprises ten steel wires twisted together with a diameter of d2; the ratio of the inner layer steel wire diameter d1 to the outer layer steel wire diameter d2 is d1 = d2 + 0.01 mm; the inner and outer layers have the same twist direction.

[0008] Optionally, the diameter d1 of the inner steel wire is 0.185 to 0.30 mm.

[0009] Optionally, the diameter d2 of the outer steel wire is 0.175 to 0.29 mm.

[0010] Optionally, the inner layer and the outer layer have the same twist direction, and the twist direction is either S or Z.

[0011] Optionally, the twist pitch of the four inner steel wires is equal to the twist pitch of the ten outer steel wires.

[0012] Optionally, the twist pitch is 10.0 mm to 20.0 mm.

[0013] Optionally, the cross-section of the steel cord is elliptical.

[0014] Optionally, the outer circle of the steel cord includes the major axis L1 and the minor axis L2.

[0015] Optionally, the outer layer is anchored to the steel wire with rubber.

[0016] In a second aspect, the present invention provides a radial tire using steel cord as described in any of the first aspects.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0018] 1. The steel cord provided by this invention can improve the fatigue performance of the cord, increase the service life of the tire, and has a cost advantage. With the same density and strength, it can reduce the amount of tire rubber and steel cord used, which meets the requirements of tire lightweight development.

[0019] 2. The radial tire provided by the present invention can reduce the thickness of the cord and the amount of cord used while maintaining the same density and strength, thus providing a high-performance and lightweight radial tire. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a steel cord cross-section provided according to an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the cross-section of 3×d1 / 9×d2 CC steel cord according to existing technical standards;

[0022] Figure 3 This is a schematic diagram of the cross-section of steel cord according to the existing technical standard 1×d1+(6+12)×d2.

[0023] In the diagram: d1 - inner wire diameter; d2 - outer wire diameter; L1 - long axis of the cord; L2 - short axis of the cord. Detailed Implementation

[0024] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations thereof. In the absence of conflict, the embodiments and technical features in the embodiments can be combined with each other.

[0025] It should be noted that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0026] Example 1:

[0027] This invention discloses a steel cord, with reference to... Figure 1 As shown, it includes an inner layer and an outer layer; the inner layer consists of four steel wires twisted together with a diameter of d1, and the outer layer consists of ten steel wires twisted together with a diameter of d2. The ratio of the inner layer steel wire diameter d1 to the outer layer steel wire diameter d2 is d1 = d2 + 0.01 mm; typically, the inner layer steel wire diameter d1 is 0.185–0.30 mm, and the outer layer steel wire diameter d2 is 0.175–0.29 mm. This embodiment optimizes the structure by designing the number and diameter ratio of the inner and outer layer steel wires, so that the contact between the steel wires has good geometric characteristics.

[0028] In this embodiment, the inner and outer layers have the same twist direction, both S or Z. The twist pitch of the four steel wires in the inner layer is equal to that of the ten steel wires in the outer layer, typically 10.0mm to 20.0mm. The steel cord provided in this embodiment has an elliptical cross-section. The outer circumference of the steel cord always has a major axis L1 and a minor axis L2, providing a channel for the flow of rubber during tire vulcanization. Rubber permeates around the outer steel wires of the cord, anchoring the steel wires and preventing the tire from failing to bond properly with the rubber during use.

[0029] In this embodiment, the twist direction of the inner layer (made of four steel wires) and the twist direction of the outer layer (made of ten steel wires) are set as S. The twist pitch of the inner layer (made of four steel wires) and the twist pitch of the outer layer (made of ten steel wires) are 14.0 mm. The inner layer steel wire diameter d1 is designed to be 0.22 mm, and the outer layer steel wire diameter d2 is designed to be 0.21 mm. Figure 2 As shown, compared with the existing technical standard 3×d1 / 9×d2, the cord diameter and linear density of the present invention are the same, while the single filament diameter is reduced by 0.015 to 0.02 mm. The test results are shown in Table 1.

[0030] Table 1

[0031]

[0032] In this embodiment, the twist direction of the inner layer (made of four steel wires) and the twist direction of the outer layer (made of ten steel wires) are set as Z. The twist pitch of the four steel wires in the inner layer and the twist pitch of the ten steel wires in the outer layer are 15.0 mm. The diameter d1 of the inner layer steel wires is designed to be 0.245 mm, and the diameter d2 of the outer layer steel wires is designed to be 0.235 mm. Figure 3 As shown, compared with the existing technical standard 1×d1+(6+12)×d2, the diameter of the cord decreased by 6%, the linear density decreased by 18%, and the diameter of the outer monofilament increased by 0.01mm. The test results are shown in Table 2.

[0033] Table 2

[0034]

[0035] In summary, the steel cord provided in this embodiment has the following beneficial effects:

[0036] 1. Increased inter-section filling of the cords increases the bending stiffness of the cords, making it more difficult for metal sheets to penetrate the cords. When used in the tire carcass or belt layer, this can effectively improve the tire's service life.

[0037] 2. The steel cord provided in this embodiment can improve the fatigue performance of the cord and increase the service life of the tire;

[0038] 3. The steel cord provided in this embodiment has a cost advantage. With the same density and strength, it can reduce the amount of tire rubber and steel cord used, which meets the requirements of tire lightweight development.

[0039] Example 2:

[0040] This invention discloses a radial tire that uses steel cord as described in any one of Embodiment 1.

[0041] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A steel cord, characterized in that, include: The inner layer comprises four steel wires twisted together with a diameter of d1; the outer layer comprises ten steel wires twisted together with a diameter of d2; the ratio of the inner layer steel wire diameter d1 to the outer layer steel wire diameter d2 is d1 = d2 + 0.01 mm; the inner and outer layers have the same twist direction. The diameter d1 of the inner steel wire is 0.185–0.30 mm; The diameter d2 of the outer steel wire is 0.175–0.29 mm; The twist direction is either S or Z; The twist pitch of the four inner steel wires is equal to the twist pitch of the ten outer steel wires. The twist pitch is 10.0 mm to 20.0 mm; The cross-section of the steel cord is elliptical.

2. The steel cord according to claim 1, characterized in that, The outer circle of the steel cord includes the long axis (L1) and the short axis (L2).

3. The steel cord according to claim 1, characterized in that, The outer layer anchors the steel wire with rubber.

4. A radial tire, characterized in that, Use the steel cord as described in any one of claims 1 to 3.

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