Steel cord and manufacturing method

Abstract

A steel cord, comprising a center wire layer and an outer wire layer. The center wire layer and the outer wire layer extend in a same direction, the center wire layer is disposed in the center of the outer wire layer, and the outer wire layer is formed by twisting, so that the outer wall of the center wire layer abuts against the outer wire layer; the center wire layer is formed by twisting at least four first steel wires (3), and the outer wire layer is formed by twisting at least ten second steel wires (4) attached to the outer wall of the four first steel wires (3).

Description

A steel cord and its manufacturing method Technical Field

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

[0002] Steel cord is an important component of tire skeleton materials. In the manufacture of radial tires, steel cord needs to be embedded in rubber. A certain company produces a steel cord with a 1×d1+18×d2 CC core layer consisting of one steel wire, a middle layer consisting of six steel wires, and an outer layer consisting of twelve steel wires twisted together. The core layer has one untwisted steel wire, while the six middle layer steel wires and the twelve outer layer steel wires have the same twist direction and twist pitch. The diameter of the core layer steel wire is d1, and the diameters of the middle layer steel wires and the outer layer steel wires are d2. This structure is formed by one-time twisting.

[0003] The produced 1×d1+(6+12)×d2 HT steel cord consists of a central layer made of one steel wire, a middle layer made of six steel wires, and an outer layer made of twelve steel wires twisted together. The central layer has no twisted steel wire, while the six middle layer steel wires and the twelve outer layer steel wires are twisted in the same direction. The twist pitch of the six middle layer steel wires is 0.468 to 0.5 times that of the twelve outer layer steel wires. The diameter of the central layer steel wire is d1, and the diameters of the middle and outer layer steel wires are d2. This structure requires secondary processing and twisting. The manufacturing process of this type of steel cord is complex, and in order to improve the strength, the thickness of the fabric and the amount of cord used are simply increased, which increases the manufacturing cost.

[0004] Summary of the Invention

[0005] The purpose of this application is to provide a steel cord to reduce the complexity of the manufacturing process. It can be used for belt layers and tire carcass reinforcement. With the same density and strength, the thickness of the cord and the amount of cord used can be reduced, thus providing a high-performance and lightweight radial tire.

[0006] To solve the above-mentioned technical problems, this application adopts the following technical solution:

[0007] In a first aspect, a steel cord includes an intermediate cord layer and an outer cord layer, the intermediate cord layer and the outer cord layer extending in the same direction, and the intermediate cord layer being placed in the middle region of the outer cord layer, the outer cord layer being twisted such that the outer wall of the intermediate cord layer abuts against the outer cord layer;

[0008] The intermediate layer comprises at least four first steel wires twisted together, and the outer layer comprises at least ten second steel wires twisted together, which are attached to the outer walls of the four first steel wires.

[0009] In a further embodiment of this application, the intermediate yarn layer and the outer yarn layer have the same twist direction.

[0010] In a further embodiment, the intermediate yarn layer has a twist direction that is SS (left twist in the same direction) or ZZ (right twist in the same direction) with the outer yarn layer.

[0011] In a further embodiment, the twist pitch of the intermediate thread layer and the outer thread layer is equal, and the twist pitch is between 10.0 mm and 20.0 mm.

[0012] In a further embodiment of this application, the four first twisted steel wires are arranged in a matrix, and the ten second twisted steel wires of the outer layer are arranged in a circular matrix, with the ten second steel wires enclosing and tightening the four first steel wires.

[0013] In a further embodiment, the diameters d1 of the first steel wire and d2 of the second steel wire are selected to be within the range of 0.185mm to 0.30mm.

[0014] A further improvement is that the gap between the first steel wire and the second steel wire is not less than 0.03 mm.

[0015] In a further embodiment of this application, the cross-section of the steel cord is a "quadrilateral structure".

[0016] Secondly, a manufacturing method based on the above-mentioned steel cord includes the following steps:

[0017] 1) Extend the intermediate wire layer and the outer wire layer in the same direction and parallel, and wrap the ten second steel wires of the outer wire layer around the four first steel wires of the intermediate wire layer.

[0018] 2) Connect the two ends of the middle layer and the outer layer to the twisting equipment and perform the twisting operation using the SS method.

[0019] In a further embodiment of this application, when the first steel wire and the second steel wire are twisted, four of the first steel wires are pre-formed in a spiral shape, and ten of the second steel wires are spirally twisted to abut against the first steel wire.

[0020] Compared with the prior art, the beneficial effects achieved by this application are as follows:

[0021] This application describes a cord made of four first steel wires in the middle layer and ten second steel wires in the outer layer, twisted together. The outer circumference of the cord always has a major axis L1 and a minor axis L2, providing a channel for rubber flow during tire vulcanization. Rubber permeates around the outer steel wires of the cord. With the same amount of steel wire, it exhibits higher strength. In actual production, the rubber anchors the steel wires, preventing adhesion failure between the steel cord and the tire rubber during use. Increased filler density between the cord sections further enhances the cord's bending stiffness.

[0022] Secondly, the first steel wire of the middle layer is pre-twisted in a spiral to increase its fit with the second steel wire on the outside, thereby reducing the possibility of loosening and improving the overall quality of the steel cord. Attached Figure Description

[0023] Figure 1 is a schematic diagram of the cross-sectional structure of an embodiment of this application;

[0024] Figure 2 is a schematic diagram of the cross-sectional structure of the existing product 1×d1+18×d2 CC;

[0025] Figure 3 is a schematic diagram of the cross-sectional structure of the existing product 1×d1+(6+12)×d2 HT;

[0026] The structure consists of 1 intermediate wire layer, 2 outer wire layer, 3 first steel wire, and 4 second steel wire. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use.

[0028] Referring to Figure 1, this embodiment discloses a steel cord, which includes an intermediate cord layer 1 and an outer cord layer 2. The intermediate cord layer 1 and the outer cord layer 2 extend in the same direction, and the intermediate cord layer 1 is placed in the middle region of the outer cord layer 2. The outer cord layer 2 is twisted so that the outer wall of the intermediate cord layer 1 abuts against the outer cord layer 2. The intermediate cord layer 1 is made of at least four first steel wires 3 twisted together, and the outer cord layer 2 is made of at least ten second steel wires 4 attached to the outer wall of the four first steel wires 3 twisted together.

[0029] The middle layer 1 and the outer layer 2 have the same twist direction, which is ZZ in this embodiment, i.e., right-hand twist in the same direction. The twist pitch of the middle layer 1 and the outer layer 2 is equal, which is 13.2mm. The four first steel wires 3 in the middle of the final formed steel cord are arranged in a matrix, and the ten second steel wires 4 in the outer layer 2 are arranged in a circular matrix. The ten second steel wires 4 surround and tighten the four first steel wires 3. In this embodiment, the diameter d1 of the first steel wire 3 and the diameter d2 of the second steel wire 4 are both selected as 0.23mm. The cross-section of the steel cord after final forming and cutting is a quadrilateral structure. The mechanical torque can be controlled during production according to customer needs to obtain quadrilaterals with different interior angles.

[0030] Referring to Figure 2, there is a 1×d1+18×d2 CC steel cord. The center layer consists of one steel wire, the middle layer consists of six steel wires, and the outer layer consists of twelve steel wires twisted together. The center layer has one untwisted steel wire, and the six steel wires in the middle layer and the twelve steel wires in the outer layer have the same twist direction and twist pitch. The diameter d1 of the center layer steel wire is designed to be 0.22 mm, and the diameter d2 of the middle layer steel wire and the outer layer steel wire is designed to be 0.20 mm. This structure is formed by twisting in one step, and the twist pitch of the middle layer and the outer layer steel wire is 12.5 mm.

[0031] Table 1 below compares the parameters of the steel cord in this embodiment with those of the existing 1×d1+18×d2 CC steel cord.

[0032] Table 1

[0033] Compared to other technologies, with the same cord diameter but reduced linear density, the cord in this embodiment 1 can improve cord strength and increase tire lifespan.

[0034] In another embodiment:

[0035] This embodiment discloses a steel cord, which includes an intermediate cord layer 1 and an outer cord layer 2. The intermediate cord layer 1 and the outer cord layer 2 extend in the same direction, and the intermediate cord layer 1 is placed in the middle region of the outer cord layer 2. The outer cord layer 2 is twisted so that the outer wall of the intermediate cord layer 1 abuts against the outer cord layer 2. The intermediate cord layer 1 is made of at least four first steel wires 3 twisted together, and the outer cord layer 2 is made of at least ten second steel wires 4 attached to the outer wall of the four first steel wires 3 twisted together.

[0036] The middle layer 1 and the outer layer 2 have the same twist direction, which is ZZ in this embodiment, i.e., right-hand twist in the same direction. The twist pitch of the middle layer 1 and the outer layer 2 is equal, which is 15.0mm. The four first steel wires 3 in the middle of the final formed steel cord are arranged in a matrix, and the ten second steel wires 4 in the outer layer 2 are arranged in a circular matrix. The ten second steel wires 4 surround and tighten the four first steel wires 3. In this embodiment, the diameter d1 of the first steel wire 3 and the diameter d2 of the second steel wire 4 are both selected as 0.235mm. The cross-section of the steel cord after final forming and cutting is a quadrilateral structure. The mechanical torque can be controlled during production according to customer needs to obtain quadrilaterals with different interior angles.

[0037] Referring to Figure 3, the existing product model 1×d1+(6+12)×d2 HT has a core layer made of one steel wire, a middle layer made of six steel wires, and an outer layer made of twelve steel wires twisted together. The core layer has one untwisted steel wire, while the middle layer has six steel wires and the outer layer has twelve steel wires twisted in the same direction. The twist pitch of the middle layer has six steel wires twisted together is 0.468 to 0.5 times that of the outer layer has twelve steel wires twisted together. The diameter d1 of the core layer steel wire is designed to be 0.25 mm, and the diameter d2 of the middle layer and outer layer steel wires is 0.225 mm. This structure requires secondary processing and twisting.

[0038] Table 2 below compares the parameters of the steel cord in this embodiment with those of the existing 1×d1+(6+12)×d2 HT steel cord.

[0039] Table 2

[0040] Compared with the existing 1×d1+(6+12)×d2 HT steel cord technology, the diameter of the steel cord in this embodiment is reduced by 7.9% and the linear density is reduced by 20%. The steel cord 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.

[0041] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0042] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

Claims

1. A steel cord, characterized in that, It includes an intermediate layer line (1) and an outer layer line (2), the intermediate layer line (1) and the outer layer line (2) are arranged to extend in the same direction, and the intermediate layer line (1) is placed in the middle area of ​​the outer layer line (2). The outer layer line (2) is twisted so that the outer wall of the intermediate layer line (1) abuts against the outer layer line (2). The intermediate layer (1) is made of at least four first steel wires (3) twisted together, and the outer layer (2) is made of at least ten second steel wires (4) attached to the outer wall of the four first steel wires (3) twisted together.

2. The steel cord according to claim 1, characterized in that, The intermediate layer yarn (1) and the outer layer yarn (2) have the same twist direction.

3. The steel cord according to claim 2, characterized in that, The intermediate layer line (1) has a twist direction of SS or ZZ with the outer layer line (2).

4. The steel cord according to claim 2, characterized in that, The twist pitch of the intermediate layer thread (1) and the outer layer thread (2) is equal, and the twist pitch is between 10.0 mm and 20.0 mm.

5. The steel cord according to claim 1, characterized in that, The four twisted first steel wires (3) are arranged in a matrix, and the ten twisted second steel wires (4) of the outer layer (2) are arranged in a circular matrix. The ten second steel wires (4) enclose and tighten the four first steel wires (3).

6. The steel cord according to claim 5, characterized in that, The diameter d1 of the first steel wire (3) and the diameter d2 of the second steel wire (4) are selected to be within the range of 0.185mm to 0.30mm.

7. The steel cord according to claim 6, characterized in that, The gap between the first steel wire (3) and the second steel wire (4) is not less than 0.03 mm.

8. The steel cord according to claim 1, characterized in that, The cross-section of the steel cord is a "quadrilateral structure".

9. A method for manufacturing steel cord according to any one of claims 1 to 8, characterized in that, Includes the following steps: 1) Extend the intermediate layer line (1) and the outer layer line (2) in the same direction and parallel, and wrap the ten second steel wires (4) of the outer layer line (2) around the four first steel wires (3) of the intermediate layer line (1); 2) Connect the two ends of the middle layer thread (1) and the outer layer thread (2) to the twisting equipment and perform twisting operation using the SS method.

10. A method for manufacturing steel cord according to claim 9, characterized in that, When the first steel wire (3) and the second steel wire (4) are twisted, the four first steel wires (3) are pre-formed by spiral, and the ten second steel wires (4) are spirally twisted to abut against the first steel wire (3).

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