Steel cord of 3 + M + N structure for radial tire

Abstract

The utility model belongs to the technical field of radial tires, and provides a steel cord with a 3 + M + N structure for a radial tire, which comprises three inner-layer core wire steel wires, the three inner-layer core wire steel wires cling to one another, M middle-layer steel wires are uniformly distributed outside the three inner-layer core wire steel wires, N outer-layer steel wires are uniformly distributed outside the M middle-layer steel wires, and the outer-layer steel wires are arranged between the M middle-layer steel wires and the N outer-layer steel wires. The M middle-layer steel wires incompletely wrap the surfaces of the three inner-layer core steel wires, the M middle-layer steel wires are woven and twisted around the three inner-layer core steel wires to form a core strand, and the N outer-layer steel wires are woven and twisted around the core strand to form the cord thread. The problems that due to the fact that an existing steel cord is too compact in structure, gaps between layers of the steel cord are small, when the steel cord is vulcanized with rubber, the rubber cannot completely permeate into steel wires on the middle layer of the steel cord, the air content of the inner layer of the steel cord is high, the steel wires are prone to rusting, the corrosion resistance, the fatigue resistance and the like of the steel cord are reduced, and the quality of tires is affected are solved.

Description

Technical Field

[0001] This utility model relates to the field of radial tires, and more particularly to a 3+M+N structure steel cord for radial tires. Background Technology

[0002] Steel cord is the main skeleton material of radial tires and a major load-bearing component, primarily used in passenger car tires, light truck tires, heavy-duty truck tires, and construction machinery tires. It offers advantages such as long service life, puncture resistance, good elasticity, safety and comfort, and fuel efficiency. The structure, strength, bending stiffness, adhesion, and rubber penetration properties of the steel cord directly affect tire performance.

[0003] A search revealed that patent CN221940943U discloses an interlaced steel cord, which includes a core layer, an intermediate layer, and an outer layer. The core layer is formed by two core layer steel wires twisted together, the intermediate layer is formed by eight intermediate layer steel wires twisted together, and the eight intermediate layer steel wires are evenly distributed around the core layer. The outer layer includes thirteen outer layer steel wires, which are evenly distributed around the intermediate layer. The twist direction of the core layer steel wires and the intermediate layer steel wires is the same, while the twist direction of the core layer steel wires and the intermediate layer steel wires is opposite to that of the outer layer steel wires. The cross-section of the steel cord is circular.

[0004] The existing steel cord has an overly tight structure, resulting in small gaps between the layers. During vulcanization with rubber, the rubber cannot fully penetrate into the steel wires in the middle layer of the steel cord, leading to a high air content in the inner layer of the steel cord. This makes the steel wires prone to corrosion, reducing the corrosion resistance and fatigue resistance of the steel cord, and affecting the quality of the tire.

[0005] Therefore, it is necessary to provide a 3+M+N structure steel cord for radial tires to solve the above-mentioned technical problems. Utility Model Content

[0006] To solve the above-mentioned technical problems, this utility model provides a 3+M+N structure steel cord for radial tires.

[0007] This utility model provides a 3+M+N structure steel cord for radial tires, comprising three inner core wires placed close together, M intermediate wires evenly distributed around the three inner core wires, and N outer wires evenly distributed around the M intermediate wires. The M intermediate wires do not completely wrap around the surface of the three inner core wires, and the M intermediate wires are twisted around the three inner core wires to form a core strand. The N outer wires are twisted around the core strand to form a cord.

[0008] To improve resistance to torque, this utility model provides a 3+M+N structure steel cord for radial tires. Preferably, the twisting direction of the outer steel wire is opposite to the twisting direction of the core strand. If the twisting direction of the core strand is Z-direction, then the twisting direction of the outer steel wire is S-direction; conversely, if the twisting direction of the core strand is S-direction, then the twisting direction of the outer steel wire is Z-direction.

[0009] To ensure sufficient clearance, this invention provides a 3+M+N structure steel cord for radial tires. Preferably, the N outer layer steel wires have a lay length of P1, where P1 = 10 mm - 20 mm, and the M middle layer steel wires have a lay length of P2, where P2 = 5 mm - 18 mm. <P1。

[0010] To increase tensile strength, this utility model provides a 3+M+N structure steel cord for radial tires. Preferably, the diameter D1 of the three inner core wires is 0.15 mm to 0.40 mm, the diameter D2 of the M middle layer wires is 0.15 mm to 0.40 mm, and the diameter D3 of the N outer layer wires is 0.15 mm to 0.30 mm.

[0011] In order to achieve the effect of filling the gaps between each other, this utility model provides a 3+M+N structure steel cord for radial tires. Preferably, M of the middle layer steel wires is 2-5 wires, and N of the outer layer steel wires is 10-18 wires.

[0012] To increase antioxidant capacity, this utility model provides a 3+M+N structure steel cord for radial tires. Preferably, the gaps between the three inner core steel wires, the M middle layer steel wires, and the N outer layer steel wires are filled with vulcanized rubber.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] This type of radial tire uses a 3+M+N structure steel cord, in which the middle layer steel wires do not completely wrap around the three inner core steel wires, improving the rubber's penetration and allowing the rubber to wrap around each cord steel wire. This reduces the air content in the inner layer of the steel cord, improves the steel cord's corrosion resistance, fatigue resistance, impact resistance, and adhesion retention, thereby improving tire quality and extending tire life. Attached Figure Description

[0015] Figure 1 A schematic diagram of a preferred embodiment of a 3+M+N structure steel cord for radial tires provided by this utility model;

[0016] Figure 2 for Figure 1 A schematic diagram of the cross-section shown;

[0017] Figure 3 is Figure 1 A schematic structural diagram of the middle layer steel wire shown.

[0018] Reference numerals in the figure: 11, inner layer core wire steel wire; 22, middle layer steel wire; 33, outer layer steel wire. Detailed implementation manners

[0019] The present utility model will be further described below in conjunction with the accompanying drawings and implementation manners.

[0020] Please refer to Figure 1 , Figure 2 , Figure 3 , a 3+M+N structural steel cord for a radial tire is provided, including three inner layer core wire steel wires 11, the three inner layer core wire steel wires 11 are placed closely against each other, M middle layer steel wires 22 are evenly distributed outside the three inner layer core wire steel wires 11, N outer layer steel wires 33 are evenly distributed outside the M middle layer steel wires 22, the M middle layer steel wires 22 do not completely wrap the surfaces of the three inner layer core wire steel wires 11, the M middle layer steel wires 22 are twisted around the three inner layer core wire steel wires 11 to form a core strand, the N outer layer steel wires 33 are twisted around the core strand to form a cord, wherein the strength grades of the three inner layer core wire steel wires 11, the M middle layer steel wires 22 and the N outer layer steel wires 33 are normal strength NT, high strength HT, extra high strength ST, ultra high strength UT or extremely high strength MT.

[0021] During the specific implementation process, referring to Figure 1 and Figure 3 shown, the twisting direction of the outer layer steel wire 33 is opposite to the twisting direction of the core strand. If the twisting direction of the core strand is the Z direction, the twisting direction of the outer layer steel wire 33 is the S direction, and vice versa. If the twisting direction of the core strand is the S direction, the twisting direction of the outer layer steel wire 33 is the Z direction.

[0022] During the specific implementation process, referring to Figure 1 and Figure 2 shown, the twist pitch of the N outer layer steel wires 33 is P1, P1 = 10 mm - 20 mm, the twist pitch of the M middle layer steel wires 22 is P2, P2 = 5 mm - 18 mm, and P2 < P1. The diameter D1 of the three inner layer core wire steel wires 11 is 0.15 mm - 0.40 mm, the diameter D2 of the M middle layer steel wires 22 is 0.15 mm - 0.40 mm, the diameter D3 of the N outer layer steel wires 33 is 0.15 mm - 0.30 mm. M in the M middle layer steel wires 22 is 2 - 5, N in the N outer layer steel wires 33 is 10 - 18. The gaps between the three inner layer core wire steel wires 11, the M middle layer steel wires 22 and the N outer layer steel wires 33 are filled with vulcanized rubber.

[0023] Three wet-drawn steel wires with a diameter of D1 are selected as the inner core wire 1, and two to five wet-drawn steel wires with a diameter of D2 are selected as the middle layer wires 2. They are twisted into a “3+M” center strand by the core machine of a double twisting machine with the twist direction being Z. Ten to eighteen wet-drawn steel wires with a diameter of D3 are selected as the outer layer wires 3. The center strand and the outer layer wires 3 are twisted into a 3+M+N structure cord by a double twisting machine (S twist direction).

[0024] The following table shows the data for steel cord:

[0025]

[0026] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A 3+M+N structure steel cord for radial tires, characterized in that, The device includes three inner core wires (11), which are placed close together. M intermediate wires (22) are evenly distributed around the three inner core wires (11), and N outer wires (33) are evenly distributed around the M intermediate wires (22). The M intermediate wires (22) do not completely wrap around the surface of the three inner core wires (11). The M intermediate wires (22) are twisted around the three inner core wires (11) to form a core strand, and the N outer wires (33) are twisted around the core strand to form a cord.

2. The 3+M+N structure steel cord for radial tires according to claim 1, characterized in that, The twisting direction of the outer steel wire (33) is opposite to that of the core strand. If the core strand is twisted in the Z direction, then the twisting direction of the outer steel wire (33) is in the S direction. Conversely, if the core strand is twisted in the S direction, then the twisting direction of the outer steel wire (33) is in the Z direction.

3. The 3+M+N structure steel cord for radial tires according to claim 1, characterized in that, The N outer layer steel wires (33) have a lay length of P1, where P1 = 10 mm - 20 mm, and the M middle layer steel wires (22) have a lay length of P2, where P2 = 5 mm - 18 mm, and P2 <P1。 4. The 3+M+N structure steel cord for radial tires according to claim 1, characterized in that, The diameter D1 of the three inner core wires (11) is 0.15 mm to 0.40 mm, the diameter D2 of the M middle layer wires (22) is 0.15 mm to 0.40 mm, and the diameter D3 of the N outer layer wires (33) is 0.15 mm to 0.30 mm.

5. A 3+M+N structure steel cord for radial tires according to claim 1, characterized in that, In the M intermediate layer steel wires (22), M is 2-5 wires, and in the N outer layer steel wires (33), N is 10-18 wires.

6. The 3+M+N structure steel cord for radial tires according to claim 1, characterized in that, The gaps between the three inner core wires (11), the M middle layer wires (22), and the N outer layer wires (33) are filled with vulcanized rubber.

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